How can I feel more confident?

Start by simply exercising. Tone what you don't like. Just pick like a half hour 3-4 days a week and be like "I am going to make this a priority." Pick out things on yourself that you do like. The next time you look in a mirror don't say "ew my butt looks huge." Say "wow I really like me eyes." Also, stop looking at people who are ridiculously perfect. They are one in a million. You can't compare yourself to others. You are an individual. While you work on your shape, do other little things to make yourself feel good. Get your hair and nails done. It always makes me feel good. Or even just work on a tan.