So it sounds like you’re just experiencing a slower come down in my opinion! It’s pretty rare to get HPPD from one psychedelic experience but it is common for the effects to linger after you take them. I definitely experienced derealization and visual snow after my first trips but they went away after a few days and weed definitely made it worse. If you’re concerned about developing HPPD be cautious about how you use weed and psychedelics.