Sounds relatable. I've always been a bit of an outsider, keep to myself, minimal socializing. Loneliness is hard, depression and anxiety are hard. I also consume cannabis regularly and know I need to stop, along with other things I would like to do but fail. I used to be a big gamer and in retrospect that was my bandaid - I could make progress in a virtual world, with friends that I rarely met IRL, and forget about the real world. After cutting myself off from gaming, hobbies became my go-to distraction and have provided some of my peak motivations. I'm genuinely happy immersing myself in the process of learning a new skill. Cannabis has been a staple throughout; just me and Mary Jane plotting my next project.
The friends I had have grown apart, people have families now and I'm still alone. I ruminate a lot too sometimes, thinking about missed opportunities, mistakes, letting go of hopes and dreams. Especially with the present economy and culture, it's easy to get stuck in a rut.
You probably do need help getting out of the rut, and it sounds like you're more vulnerable about your situation, which you'll need to be to accept help. It's a shame you couldn't get a stimulant because I was thinking that might help, it helped me a little. I was prescribed one for ADHD a long time ago and was worried it sort of fried my motivation circuits, so I stopped taking it for a decade. I got back on it a few years ago because I was really feeling stuck. That's the only diagnosis or medication I take though so idk how that might work in your case. Maybe get a professional to look over your medications and see if the side effects from one might be a problem.
Anyway stimulants only help so much, one problem I've noticed is it drives me to write really long posts online that take a lot of my time lol. I should be doing a bunch of chores right now but as soon as I get off work and get high I'm toast and end up putting that focus into less meaningful tasks. There's tasks I've been putting off until the weekend, for the last year, and even if I take an adderall on my day off, it still doesn't get done. It's fascinating lol, and frustrating.
It's not easy for some people like you and I to quit cannabis. I've taken a few breaks this year, longest was ten days. It makes a difference and will make an even bigger difference when I manage to take a substantial break. There's a support group on reddit with ex-users sharing their stories and tips. You can do it!
See if you can get family or a friend to help you with basics for a bit, like cleaning up, organizing, applying for work, eliminating whatever little things are making your situation feel overwhelming.
Also, force yourself to be around other people, like a roommate or workplace or situations that you have to be somewhat presentable and responsible. Otherwise, at least for me, if I know no one's coming to visit or I'm not going to speak to anyone, the motivation to clean up or brush my teeth just isn't there. I was fortunate enough to work for myself, from home, for a year; and got away with being way less responsible. Now I work for a company, which is nice to feel like part of a team, and it's a serious motivator to be presentable and cease cannabis use, at least for half the day.
DMT might help shock you out of your status quo, but you'll still need to take steps and build a support system to sustain a transformation. It's hard work to integrate a dream.