This sounds like an horrendous situation that you find yourself locked into. I agree with the previous poster (Tart Cherry Jam) that stepping away from the online world should be a priority. I assume this person only knows you as an online presence, and that he has no idea of your real name and actual location? I hope this is the case, otherwise I would advise contacting the authorities and report the facts about this abuse.
Again, echoing the previous poster, the online world can be a terrible place to live out your life. It is totally fake, and I understand the irony of the fact that I am replying to you in this same online world, but hopefully a much safer part of that world.
Close your social media accounts, stop interacting with this individual. If he has your phone number, change your phone number. You will begin to feel much better in a very short space of time.
Do you have parents, friends or counsellors that you can talk to - real people? This can be so important and help put things into perspective for you.
Your life is so valuable and precious. Don’t let this destroy you. I’m not sure what support networks are available in the US. Here in the UK we have an organisation called the Samaritans, who you can call any time of the day or night and talk to a real person about the problems you are experiencing. I would imagine there are similar support lines in the US. Please think about finding ones of these support lines and call them.
Best wishes,