i’ve been having hallucinations what can cause them??

hello i’m not diagnosed with schizophrenia but i don’t know where to post about this. I’m in my 20s so i’ve been having hallucinations for years and they just keep getting worse, first i would see this shadow man at night that would disappear when i blink my eyes (i would see him for like 3 seconds or less)

I also had this hallucination when i saw my mother at my place and followed her upstairs but she was at work but i didn’t get a lot of sleep that day so i thought it was because of that. It’s not the first time i make excuses for this kind of behavior when sometimes there’s absolutely nothing wrong and i still have hallucinations

last week i saw a creature like a monster running right in my direction now i’ve been hallucinating dead animals (i opened the door i saw my cat dead) and he was alive but i saw him dead. And a lot more i’s really weird. I keep trying to talk to my family about this but they don’t take me serious. Can someone tell me what could be causing this??