I hate my body. I look in the mirror and wonder how anyone can look at me without gagging. I am a 15 year old boy wants desperately to gain weight. Am I the only one who feels this way?

I have been skinny my whole life. I never was as tall or thick as my friends, but it never bothered me. Some kids started making jokes, but they always passed. But that all changed in middle school. Locker rooms meant guys seeing eachother shirtless every day, and pretty soon people realized how thin I was. It started with quick jabs "Hey there, how was the halocaust jew?" They would say. Eventually I had hid my body away so far no one could make a move. I take down all my mirrors because I can't stand to look at myself. I can't stand to see myself after a shower because of how my bones show through my skin. If there were any way for me to gain weight I would. And I eat more than 3 meals a day and I always feel full. I routinely go pick up chipotle and wendys after eating a full meal at a resturant. My fast metabolism is my most hated feature about me. I am 5'7" and weigh 115 lbs. as of this week. Should I be beating myself up this much? Or am I really