I had been using high doses off and on fairly regularly for maybe eight or nine months, mostly alprazolam, diazepam, and temazepam, generally two of those concurrently (at least until the scripts ran out

).
Gabaergic tolerance, dependency and withdrawal can be a really strange beast. The detox and PAWS changed over time. It was never an issue before, but this last relatively period of more frequent, higher dose use ended up leading to a more difficult experience coming off. Even if it wasn't a big issue before, I wouldn't be surprised at all if your experience of anhedonia is the result of coming off phenibut again.
Any exercise is great, although aerobic exercise (again, it doesn't need to be hardcore or anything, just like an hour of walking helps a lot) is what is really supposed to help the most with depression and mood disorders. But if you enjoy lifting, go for it! You can always take the long road walking to wherever you good as well.
I understand about having a hard time with the socializing. It was really hard for me to get myself to do in early recovery, but frankly it had more to do with the fact I didn't feel like my life had any meaning more than anything else. What made a big difference was finding likeminded communities and people it was a genuine pleasure to spend time with. That made it infinitely easier and more possible to get myself to do. Truth be told I still have a bit of an issue with spending a lot of time on my own, but it isn't exactly unhealthy anymore.
Always happy to help, it's why we're hear
You sound like you have a good head on your shoulders. If you feel like you need some kind of relaxing substance that is gabaergic like try out some kava tea. It shouldn't cause you problems like alcohol or other gabaergic substances, although it won't exactly get you fucked up either. But it can be a relaxing little treat.
Keep up the good work!