Jason,
Glad you are doing a little research. Firstly, your advanced education is about the most irrelevant thing in your post. You are an addict. You are way beyond a home fix based on your story. You are being enabled by those around you. Perhaps they are holding on to your past as a bright kid.
Regarding your questions;
*If you have no emotions and are perhaps thinking of sobering up, sex is the last thing you should be thinking of.
* Of course you can't sleep, you are drugged up the wahzoo, and your brain and body don't know what side is up?
* Will you ever be the same? Yes, if you give up all that crap now and let your poor brain develop. It is pickled at present and you are stunting your emotional development.
Lastly; often, gifted children do NOT become successful and develop to their full potential for many reasons. Perhaps you could examine why you seem to be on such a mission not to benefit from your smarts.
Good luck, and try and organise a no-nonsense rehab program for yourself.