Hey! I'm actually in a really similar boat, was feeling better until I started drinking again and now I feel almost as bad as I did when the PCS first started. I worry a lot about the possibility of permanent damage, and I barely ever feel like myself.

It's really hard to not drink / smoke weed / etc. when you're in an environment where everyone else does it. That's just how most people our age socialized and have fun. But I think you're on the right track by avoiding alcohol and exercising.

If you're worried about recovery, you should check out the hope and healing thread on this forum. It's helped me through times when I was terrified I'd never recover. If people with severe / multiple concussions can make a full recovery, I believe you can too.