I just want to be thin.

I'm 15, 5'4", and I weigh 112 pounds. Ever since at least third grade, I've been very self conscious, never quite understanding why I looked so different to everyone else. I was never overweight, nor did I look it, but I always felt that I was fat. I didn't have the same thin long legs that the other girls had and when I got to middle school, I noticed that all the other girls in the locker room had flat or soft tummies, but not like mine. If I wear my favorite jeans, I get a muffin top. In eighth grade, it got really bad, and I started to self harm, cutting words like fat and the number I weighed onto my thighs. I was really upset and I just felt awful. Ninth grade was pretty much the same too and I skipped lunch most days. My mom has always been very observant so I knew I couldn't fast at home, ever. At the beginning of eighth grade, I weighed 125 pounds, but since I lost that thirteen, I haven't been able to lose more. Now, I'm in tenth grade and I'm too scared to wear shorts to school, despite it being 90+ degrees outside. My best friends are both really thin girls, one of them because she's fit and the other because her medication makes her not hungry. A lot of the girls at my school are thin too, or really pretty. I'm not either. 
I haven't self harmed in nearly five months, but being back at school, I find I don't have the time to work out anymore, and I feel like I'm falling again. I guess this was more of a rant than anything else. Im sorry if this topic was supposed to be only questions...