Yes, you sound depressed. Can you get counseling at school? That would help, I'm sure. Overeating for comfort is something I still do from time to time. Carbohydrates are endorphin-producers, feel-good foods. Till they are on your hips, then, that's a different story. And I relate to the envy of your sister as well--my mother always favored my brother and younger sister over me. So I understand that pain, too. Feel free to vent here anytime--you'll find a lot of us are willing to listen and share our thoughts with you.

What should you do? Take things a day at a time for while. Don't try to fly to the moon, just get thru what you need to do for today. Set some goals, but break them out into little pieces. Like: I want to lose weight. OK, so, just for today, I'll exercise instead of eating fries with my burger. Just for today, I'll eat an apple instead of a snack before dinner. Then get up tomorrow, and do the same. The days will add up, the jobs will get done, and you'll lose some weight and feel wonderful.