I'm not going to tell you he does or doesn't love you. It's not my place.
However his actions are clearly telling you he isn't in a place for a relationship right now. At least not the kind you need and deserve.
Post rehab is difficult and emotionally tumultuous time for many of us. And there is a high risk of relapse as well.
It could be because he started using again, it could be because he's just not emotionally available. It could be because he blamed you somehow for his addiction (us addicts love to blame other people) or he could have met another girl in rehab (which is guaranteed to end horribly) I'm not saying any of this to hurt you just as an outsider looking in.
I've been in this situation before with one of my exes. He wasn't an addict but one day he just stopped calling, stopped responding, we were long distance as well. Told me he needed a little space but didn't want to break up. About 6 weeks later he changed his Facebook status to single and I never heard from him again.
I knew for a long time, deep down, that things weren't good, that he probably didn't really want to be together but his WORDS told me to just hang out and give him some time, well his ACTIONS spoke differently. But when we love someone we really want to believe what they are telling us.
My advice to you is to focus on yourself. Maybe try to attend an Al-Anon meeting. Do something for yourself. Get your hair done, your nails done, go out with your girlfriends, do something that is just about you.
And tell him you need an honest answer about the future of your relationship. But remember not to just take his words at face value. His actions have to match them.
Best of luck to you. I know how hard what you're doing through is. And most of this is so much easier said than done.