It's all about self confidence. You described yourself as a fat girl. But you're more than that. Focus on your best qualities. Self esteem and self confidence are the most attractive qualities a lot of the time. And anyone that can see that there's more to a person than just their weight isn't worth your time anyway.

Don't worry so much about a cute guy.
Find one who appreciates the person you are inside, where it counts.

If they are so shallow as to let appearance dictate their actions toward a person you don't need them around anyway.

If you have to change yourself to be with someone, do you honestly want to be with that person