Regret

This is a post I'm far from proud of. I don't regret anything in my life, so feeling this feeling makes me feel indifferent and very unsettling. So please, to those who are reading this, don't judge me for what I'm about to say, and if you do then please keep those hurtful words to yourself.
Claire is the topic of this entire post. Every time I say, she or her, it'll 99% of the time be speaking of her. Otherwise I will clarify things to make the references more pronounced.
Last year, Claire was doing very poorly and we had thought of keeping her back in 3rd grade. For the thought process of that messing her up and also seeing her grades improve, we allowed her to move forward.  This was a mistake that we will forever think was a mistake. It has been incredibly difficult seeing how backwards she's gone this year. Between her growth in her schooling and her maturity levels, it's almost been traumatic for us as her parents.
Claire's focus in school was exposed when I found some letters to boys (not just one, either) expressing how she missed them and misses their touch and can't wait to marry them. Okay, so I can see the missing of one of the boys (he moved) but to exclaim that she misses their touch is extremely disturbing to and D. She is definitely worrying D and I in ways words can't put in detail.
In addition to that, her grades are slipping and she chooses to do little to no homework and claims that she never got homework. But then, come 3-4 days into the week, she then has a workload for the entire week to catch up on.
Then her teachers have given her resources to guide her in the right direction for taking tests and she just never gives them to us to help get her to. This morning that was exposed by her teacher when D went into her school to ask why she had an F in Science. 
Now, that's just school related but school issues will pop up in this next section. I want to say that we lead very busy lives and while time is against us most of our days, there has never been a time when we wouldn't put everything on hold to help her, but it's come to the point where I can't give time to someone who doesn't care enough about her schooling. I will not waste my days on a person who just doesn't give a crap about not only herself but also the teachers who are also trying to help guide her in a positive direction.
Okay, onto home life... Claire has definitely been one to sneak things in the past but over the past couple of months, it has become very much out of hand. Let me start this part out by saying, most of what she asks for I have no problem saying yes to. In fact, I praise her for asking instead of just taking or doing.
1) She has been sneaking into our bedroom and stealing my jewelry and taking it to school. The way I've found this out is by her dropping it in the bathroom or her bedroom as she attempts to sneak it. She has taken things from me and denies it until I state that I know she did it and then show her the evidence. 
             - She stole a necklace charm that I've had since I was little and said "I thought it meant good luck." I replied with "Stealing things doesn't give you good luck regardless of its meaning."
2) She takes my body sprays, and perfume to school and when they go missing, she is asked where they went and denies that she takes them.
3) She steals my make-up and states that I don't know what I'm talking about when I realize.
           - She has taken my hypo-allergic foundation and washed the brush to apply it.
          -She loves the color blue and magically 80% of my blue eye shadow is missing. Mind you, I do not wear blue eye shadow. I have it because it is a duo type of container which has black on the one side. Once again she denies doing such things and says that I don't know what I'm talking about.
(Side note, I know little girls like make-up, however she is way too young to be stealing make-up from me)
Now onto other things she has been sneaking...
Food:
So this has been an ongoing problem for months and may I say SEVERAL months. So much that we bought a utility cabinet to place in our basement and a door lock for our basement so she can't get into the foods she is only allowed to have when monitored. Claire doesn't seem to understand that all of the food we give her is so we can prevent her long history of family with diabetes. 
Claire has actually used our kitchen drawers as a ladder to climb into the highest cabinets and get the snacks which were in that area. We placed them out of reach so that she couldn't reach them and be damned if she didn't disobey us by doing something (climbing on cabinets) to get something we've told her is not for her snacking when we're not home.
A couple of days ago, my cat Ebony, was being rather mean to the other cats. She was in Claire's room under her bed hiding. So I shut Claire's door to her room and began to move Claire's bed to get Ebony out. As I moved her bed, out fell a ziploc bag with several pieces of trash wrappers from candy (which we don't have at home and have told her teachers not to give her any candy because out our family history and they have honored that request.) along with 2 tupperwear containers. One of them had a good amount of peanut butter in it. The other was a container which had once housed her birthday cake. She said that she had them from school. Okay, so let me fill you in, the peanut butter was given to her with her apples for school lunch 6 weeks ago. The peanut butter was clearly fresh and being snacked on while she wasn't being monitored. 
In addition to what was in that bag was my body spray and 2 spoons. While spoons doesn't seem to be a big deal to you all reading this, it is because we had been losing spoons left and right and before I went to buy new ones I asked if she knew where any of the spoons had gone and she said she hadn't an idea. So I bought new spoons for the matter of losing so many. So that's a big deal because she lied about it.
So, that evening I began tearing her room apart, man the findings seemed endless. I pulled apart her bookshelf to separate the important stuff from the crap that she has accumulated and found:
-A write-up from her school which was hidden still in the envelope in which it was given.
-A letter from her music teacher asking for parents to buy recorders for their children so that the children don't have to share ones with other students.
-2 more spoons
-A yogurt cup
-Letters which she wrote, indicating to students that Maroon 5, Jay-Z, and Linkin Park were all going to be performing at their school.
-Love letters to the first boy, Anthony which she stated she had kissed and wanted to spend more rime doing that with him.
Then her nightstand had quite interesting findings:
-In what was to be used as her jewelry box was a box of banquet maple sausage, empty....
-More of my perfumes, make-up, and jewelry.

So, this has been very rough for us as her parents to see. We're truly at wits end with all that has been happening here in our household. D and I feel so disrespected and out of options. She is still writing letters about how she hates herself and several thoughts that make it seem that D and I aren't good enough parents to her. Our stress levels are though the roof.