It is hard to sustain interest without actually meetings a person. I hope you understand that those aren't actual dates and it's not actual sexual interaction. I think it's normal to start losing interest since the only interaction you have is a phone and a computer screen. Also it's very time consuming. He might be busy.

Are you doing anything besides being online? You graduated high school at 16, it's impressive. Do you work? Are you in college? Do you have hobbies? I dont think it's healthy to be that much online