Torn, a lot of the projects I have for school are group projects too. I think it adds a nice dynamic. When I'm feeling particularly motivated, I'll take on a huge chunk of the project and then bask in the praise of the other people in the group. Conversely, if it's something I don't understand or don't feel like doing, I'll free ride and play a game of chicken waiting for someone else to do it. I definitely feel my anxiety running high when that happens since I feel like I'm letting the group down and that someone will get mad at me, but honestly, sometimes I just need that.
Also, I've told myself the same thing a few times about "why did I quit now?" For me, I know the answer is that on Feb 19th I got completely obliterated on a WEEKNIGHT and woke up in the hospital and missed work due to drinking for the first time in my life. That was really pretty scary as I'd previously been only binging like that on weekends and on weeknights, had "controlled binges" where I drank early enough that I'd get to work on time.
60, sorry to hear it was a bad week, but you made it through it sober, and that's what's most important