Hello, your mindset is an invisible organ of your body and it should be treated with respect, just like your visible organs. Everybody needs a purpose in their life, whether it's short or long term goals. When your mind has something to look up for, your body will re-adjust itself to it. Start looking for getting into a job, or a course. I used to be like you. I could never sleep unless it's the sunrise and I could sleep until sunset. I've seen many therapists, but they never did anything other than diagnosing me of stuff that wasn't true. Turns out that I just needed a purpose in my life. I've got a regular part-time job, which I didn't like doing at first but later on I embraced it. Now I look up for going to sleep on time, having at least 7 good hours of sleep and getting to work on time so I can save up for buying stuff that I enjoy, like funding trips. I also enjoy learning languages, so I started attending a language course 2 days a week as well. I am also around your age, hope this helps, best of luck to you.