How do I convince myself?

I feel horrible right now. I feel tired, unmotivated, dehydrated, and fat fat fat. I know, fat is not a bad thing. But right now, in my brain, I can concentrate on nothing but the bulges of my body and how my clothes don't fit right and how I had a double chin in a picture that my brother's wife took the other night. I haven't been this big in years, and it's really getting me down. I keep wanting to revert, to give in and start counting calories again, if only just until I've lost weight again. At very least, I would like to fit my clothes properly. I don't have money or desire for a new wardrobe.
I know it doesn't make sense. I know there's nothing wrong with fat. I know that I think that certain people in my life are fat and I love them think they are beautiful and I love that they're positive about it. But when it comes to my body, even at my skinniest I felt like I had fat, jiggly, cellulite-pocked thighs. I used to dislike being fucked in ways that made my back fat crease (or, as some would say, my skin.) And now, now when I am (or I feel I am, I don't actually know) as big as I was before I reached my goal weight in second year of uni, I have a hard time reconciling myself with it. Fat is what I blamed all of my problems on in middle school and high school, why I stayed in a relationship that I probably should have gotten out of, why I felt the need to slut myself out to people that I wasn't really attracted to at all. Fat has been blamed for rather a lot in my life, and it doesn't help to have so many people around me buying into the shit that I hate but subscribe to as well. How was I supposed to feel like I was enough for JF when I was fat/chubby when his comments about how hot I was increased a thousandfold when I lost weight? (It should be said that he said that I was enough, but I think you can see the disparity in the pattern, or maybe that was just me being overly sensitive to that sort of thing.) How is anyone supposed to feel like they're enough, in this bloody society where putting yourself down has become a spectator sport? I honestly and truly hate that I feel this way about myself. I want to love my fat. I want to be able to feel like I can be whatever and I will be loved no matter what, but there's something in the way, and I don't know what it is. But in the end, hating any part of myself, whether it's the horrible impulse to restrict (and hate) myself or not, is not conducive to actually getting better and being able to accept myself for what I am.
I need my Sark book back from SC. And possibly to borrow some books from S. And to read Osho. But instead? I have to study for bio, because otherwise I'm going to get another B on my test and I can't have that. Do you think I'm much of a perfectionist? Fuck.