I agree with jeminijad. You need to be bulking up your meals with low-cal stuff, especially at first. It always takes a while to get into the swing of things, break bad habits, and let your stomach shrink and your tastebuds adjust to not eating so much junk anymore. You can make some HUGE calorie deficits by swapping out higher cal foods for lower cal ones while still consuming the same volume of food. In fact, there was a book written about this a while back called "Volumetrics" and if you google it you can find a bunch of ideas/suggestions.
One thing that I have had to realize is that it is NORMAL to be hungry sometimes. As many people on 3FC say, "Hunger is not an emergency." I try not to get too hungry because I think that can lead me to making bad food choices, but when I started losing, I realized that I hadn't let myself get truly hungry in probably years. Losing weight is not an entirely pain-free process, you DO have to limit yourself, control yourself, and be conscious of what you are putting in your mouth.
Great job on giving up the soda. I think it is a good idea to start small and work up to bigger things, it is probably more sustainable that way. I was listening to a piece on NPR the other day and they were saying that scientists have done a bunch of studies on will power and that will power is essentially like a muscle- the more you use it, the stronger it gets and the easier it is to use. They did one study where they told people to be more conscientious of their posture for a few weeks, and at the end, the people who were watching their posture had an easier time losing weight, quitting smoking, etc., than did the people in the control group who were not told to do anything. Think of quitting soda as "practicing" for future calorie restrictions. You are gonna do great. Results don't come overnight, you just have to stick with it. You seem really young- it's great that you're doing this now. I know you know that being big will cut your life too short- that feeling of being over-full isn't worth a longer life! You can do this!

