Whats the best way for me to tighten my stomach and lose a bit of weight?

I'm 19 yrs old, about 5 ft 5, and about 180 pounds. I'm on the depo shot.

I've been trying to do Flirty Girl Fitness (I bought the dvds). I've got a bit of a pudgey stomach and don't like it. I've been trying to eat healthy, but I can't stand most of the foods that are healthy for you. I've been getting back into biking recently and I've been thinking of getting back into swimming and I'll be walking a lot if I get a dog.

What are some other things I can do that will help me out?

Don't tell me to go on a diet, it won't work for me. I do eat fruits/veggies but not enough, and I can only handle salads once in a while. My main diet consists of pizza rolls, pb&j sandwiches, oatmeal, amp/monster, mr. pibb or hi-c, and kool-aid. I also eat a lot of McDonalds as thats where I work and since we can't leave the premisis its either that or not eat (i get really sick and migraines if I don't eat). I eat about twice a day, its all I seem to need as even a small amount of food can last me nearly the hole day. I also sleep a lot when I get the chance (10+ hours) and about 4 hours a night the other 5 days a week.

So what can I do to tighten my stomach and lose a bit of weight?