I am depressed because im FAT!!!!!?

okay so im one of the most depressed girls you would ever meet in my high school. one because im obese im 165 and 5'3.. i know what your thinking, but hey im trying sooo hard to lose everything i really am! i joined softball and amazingly made it to the varsity team, i run a mile three days a week (if im not busy watching babies) and do sit-ups in my room when i am doing homework. I try so hard to do all this but the second reason that i am depressed is because my foster parents! they are so unsupportive, like for example i ask them if they can take me to the gym, they reply "why should we? your just gonna break there equipment" it hurt my feelings so bad that i starved myself for a week, and i cried my eyes out! then there is my foster sisters, im a jeans and t-shirt kind of a gal, and they are as girly as girly can be! they are constantly criticising me calling me a butch ( basically) and they are saying that even if i did lose weight i till wouldnt look good in anything.. but ive heard im pretty from people but im overweight so its a "turn-off" it sucks! im over it!!! please help me!!!!