I AM SICK OF THIS HUGE FAT ROLL...I DON'T WANT TO BE LIKE THIS ANYMORE (10 PTS)!!!!?

I am a senior girl in hs & I have a humongous fat roll on my stomach. I used to weigh 110, but then I got all stressed about not having a prom date (it's over now) & I gained 30 pds. I am now 140 & although I am still considered "a healthy weight," I am on the verge of being overweight & I am not satisfied w/ my body. My old clothes don't fit anymore. I rotate between like 3 pairs of jeans, & I can't seem to lose it. I have a poor diet. I used to eat heavy unhealthy school lunches but I get out of school Fri & will start eating: B: cereal/OJ L: turkey sandwich/animal crackers/pickle/choc pudding cup D: usually pasta/veggies/salad So what's the problem here? Obviously the heavy school lunches right now, but that will stop. Is this healthy to eat every day? Also, I get NO exercise at all. I keep begging my parents to get me an exercise machine, but they won't get me one b/c they don't think I will actually use it & I WILL ACTUALLY USE IT. But I'm pretty sure even if u eat healthy, if u don't burn off everything u eat, u still gain weight, don't u? I'm meeting a childhood friend who I haven't seen in YRS in a couple weeks, & I don't want to look like this. Not only do I have that fat roll, but my face & thighs are bigger. I sent him a pic of me at the beginning of this yr b4 I gained all the weight so he's going to wonder what happened to me. Also, almost all of the girls at my school have NO fat roll. They are skinny and perfect & some of them eat heavy lunches like me so what is wrong w/ me? Plz help me!! And if u can think of any healthy snacks or any exercise I can do w/out leaving the house & w/out a machine, plz let me know. Thx!