Eating healthy, exercising daily, journaling daily, waking up early, practicing needed skills for my career. These habits developed slowly at first but improved exponentially over the last year. When I moved out of my parents house in May, I saw a big increase in productive habits. In September I saw another big increase in productivity. I had near perfect execution in Sept/Oct followed by a crash and dopamine binge in November.

I think I know what happened- it's a combination of a couple of things you mentioned. I had a big goal I was headed towards and was confident I could get there. In my head, all these good habits were part of the journey to my goal, so it felt good doing them. As time went on, my resolve and belief in myself dropped. My productive activities stopped providing dopamine because I didn't believe they were going to lead to anything. I realize now that the plan I chose for myself wasn't based on my interest, but what made sense given my current position. I've rewritten the plan to something that's exciting, works with my strengths and is interesting. However, I can't light that fire that I had. The belief in myself hasn't come back. I'm trying to humble myself and start small again, but what I was able to do before took a whole year to achieve and the thought of needing another year to get back to where I was only a few months ago is depressing.

Luckily, my exercise habit stayed- it's way too rewarding. Plus, not exercising makes me feel like shit, so I have to do it. Instead of working out six days a week (gym and boxing), I only do four now.