Whenever i eat, i ALWAYS need a big portion. i hate sharing food because I "need" to have it all, and this problem is leading to weight gain. my boyfriend try's to help me by splitting my portions in half, but i literally will not eat if it's not a lot of food. I sometimes force myself to eat smaller portions, but I get very miserable feeling and start crying and How do I stop thinking this way?

This could be some sort of eating disorder. You must attend to take professional help.

Try using a smaller plate, drink a full glass of water before you eat, and this does sound like a compulsion....at least talk to your doctor about it.

I agree with Matt, that it seems you may have an eating disorder. You should really talk to you doctor about this. Until you can get into your doctor load you plate up with veggies, preferably steamed or raw. They are filling and do not have the high calorie count of other foods.