Hi elevatedsoul, yes I'd say that those feelings could definitely be part of your anxiety.
I can completely understand if you're feeling old as you've been through/are going through SO much BUT.......24....really not that old!! And plenty of time ahead of you to have so much you're proud of to look back on!!
ALTHOUGH I'd say that you have already come so far/have already got things to show for it......massive reduction in drink, MJ........!!!
I know you've still got a way to go yet in managing things and that it's really hard for you but everything you can tell your therapist and pdoc is going to be a step (however small, still a step) in the direction you want to be going in.
As for other people having it worse, that takes nothing away from how you're feeling now and it's just as important that you get the help you need!!!
The medication......I know, still in the stages of trial and error (?).........but it can take time to find something that is really right for you personally, hang in there!!
And, I'm really sorry, but I can't remember if I asked you before if you were having contact with AA or any drug support groups. Maybe they could help if you're not???
And remember, as ever, we're here for you.............
Alison