Hi Mariya,
Get help is the only answer I can give you. I don't know your personal struggles, but I do know that there are trusted adults you can go to. First, if you trust your parents, go to them. Or an older sibling. If you can't trust your family, there are school counselors, spiritual leaders (pastors, priests, rabbis, etc.), the school nurse, etc. And, while you're doing all of that, SAY NO.I know it won't be easy to quit, but your health and possibly your life are at risk. Quit at all cost, and find someone to help you. Not online-- a real, tangible human being who you can talk to, see, and trust. I know this isn't accepted by everyone, but I will pray for you, if you will like. My God can help you if you let Him. Even if you are religious, please find someone to talk to about this. Thank you for asking a question that is on a lot of people's hearts.