I went through a sort of existential crisis after my second mushroom trip, I don't remember well if I had big problems with sense of time/space, but it really did turn my life upside down. Mainly from questioning everything I did before, and whether I really chose them consciously or just kind of passively adapted to my own life.
I'm sure it is not really possible to compare yourself to other people or how long they take to go through such a thing, but it took a few years for me in total. I got heavily into philosophy and also into spirituality to some degree - getting a good feel for Zen buddhism because of my mystical experience and the ones that followed that initial one.
The first 6 months or so after that impactful trip, I pretty much did not touch any drugs because of how shaken up I was - after that I decided to go back to psychedelics (which meant mushrooms as I could get those legally here in the Netherlands and was not well into the psy scene yet). I "reasoned" that it might take the language psychedelics speak to resolve the issues that had also arose from them.
- Tripping after that, especially extreme tripping on things like LSD combined with K for example, could take me further away from home. To some extent tripping in general did help as I learned valuable lessons and could start answering some of my questions, but because I also got new questions in the process, they didn't shorten the time to 'recover'.
- On the other hand, eventually when I could 'conclude' this crisis or process and philosophy became more of a benign background interest rather than a quest I had to solve before anything else could have meaning again... I came out a more conscious person than I was before who has learned a great deal about certain things out of necessity. I am thankful for a lot of it, but it is easier to be thankful when the difficult part is pretty much over.
Depersonalization and derealization don't sound like they really have positive sides to me, neither does a crisis, but if you are able to at least turn this into a process that goes somewhere that might have you end up even better than you started... that would probably be better than just being lost, with no point to it.
Then again, please don't make too many of the same mistakes I made, if you really go on such a quest to re-answer (or answer for the first time) your meaning of your life in some sense... I made my process more complicated by losing balance and structure in my life, in part because I have ADD and ASD... and just doing too many drugs. Not only things like addiction or health issues but also complications from tripping too much can exacerbate your condition, and there are real risks involved with losing sight of difference between reality and fantasy.
I never suffered from issues with that distinction, but if you do as part of your derealization, that means tripping is way risky for you. Smoking weed is also not good if you're fuzzy on certain things, but that also isn't worth it anyway as it is less therapeutic or therapeutic in only different ways.
I recommend that you first remain abstinent a lot longer so that you can see the dust settling. You may still have issues but you should become more aware if your issues are more existential crisis, DP, DR, HPPD or differently related. That should help you avoid things that would exacerbate your situation and instead choose options that are best suited for your problems.
By the way I do have plenty of experience with sense of space and time distorted and impaired chronically from dissociatives, and that goes virtually back to normal but it just goes very slowly, and you have to quit using them of course. It can take way longer than the weeks it's been to say anything about those kinds of problems. So again - stay confident and wait a lot longer, seek help / counseling / symptomatic treatment if you have trouble functioning and bide your time some more. Question yourself about the real core of the issue and whether it relates more to difficulties knowing what's real or feeling real, or rather feeling different and awakened somehow and having to re-answer all those questions? Is the problem more delusional or the opposite: feeling too 'real' as if you unplugged from the matrix. That would of course feel so alien in the beginning, but on the longer run is actually based on being more conscious about very real things, and taking control over your own life in the process.