First off I think you have accomplished something amazing especially at your age! CONGRATULATIONS!
No one can take away what you have accomplished! There are many older than you who dream of doing what you have done! Just make yourself a promise never to go backwards. You sound too smart for that. Get back into counseling - one on one since it worked for you and maybe group would be interesting as well...
When you feel that urge and have no one to turn to I am sure that your counselor would have given you a hot line to call but there are national gay numbers to call *if you feel more comfortable using one of those!
Concerning friends, the thing is you have a history, an addict history... most people dont understand that addiction usually is a physical as well as a mental disease. Maybe you can convince your school to bring in a speaker about addiction... just a thought.
Are you doing better with your grades? Do you have plans to attend college or uni? Do you have a job? Those kind of things, current job, future plans, will keep you going and bring a new life/friends along.
The exercise is not only good for you mentally but will get you all HOT and maybe find a new boyfriend while you work out! Working out, running, cycling is one of the best natural highs ever
Good luck and hope this little forum will help a bit