How do I eat more calories?

I've been at 120-125 for a couple of years now and I'm about 5'4.  I reall want to get back down to 110ish like I was a few years ago.

 Any weight I gain goes straight to my butt and thighs. My stomach likes to extend as I eat more. But as I eat meals I get full quicker.When I'm snacking, I just eat eat eat. And the snacks areM&Ms, Reese's, popcorn, anything. And then there's pop.

I decided to try to start eating healthier a week or so ago and I'd been looking at the calories of the foods I eat and I realize, I eat no more than 700 or 800 calories a day and I burn at east 400 a day usually by walking to classes on campus. So if my body needs 1200 calories to function, why am I still functioning and why have I been functioning with no problems? On the outside I look healthy but I'm wondering what's going on inside of my body.

So I try to eat healthier but it's making it so I eat even less calories than normal because healthy food has less calories than a pack of M&Ms. So how do I eat healthy and still get those 1200 calories a day? (Mind you, I live on a colege campus on a college budget)

it's easy. Just eat as many vegetables and fruits as you like until your full! :)

bananas, clementines and appleas really fill me up! (apples and bananas have more calories to)

Dairy products such as milk, yogurt, and cheese.  Tofu also works.

Brown rice. It's cheap, high calories and healthy. Bananas, grapes and yogurt are good for snacking on too.

Peanut Butter or nuts. High calorie and portable so you can take them with you to class.

by eating more calories. ^_^

I'm a college kid too, so whenever I need a bite and am running out the door I take a slice of whole wheat bread, spread 2 tbsp of peanut butter (go store brand, wooo!), and fold it around a banana, like a hotdog. It's easy to eat with one hand (always good when you're late for class......again!), and really easy and quick to make!