I used to write alot of poems when I was your age...many many moons ago. It really helped me to twist words and play out my feelings on paper. Most of my problems were because I got caught up in the wrong crowd...wanted to hang out with the cool kids...but the first thing I was told in rehab was to change your playground and your playmates. Have you been doing that?
I'm sorry about your girlfriend...but from your poem it sounds like she's causing you undue heartache because you aren't using. I think you are more you without using...drugs issues a falsity on your personality.
I think at this point you know whats right and wrong...at 16 I knew everything. (That's a joke! LOL) But if she doesn't want to be your girlfriend then that's one less person you have to axe off your using list. I wish you the best of luck in continued sobriety. I think you are doing really well. Glad you are posting your thoughts.