Weed is a psychedelic, just like LSD, psyocibin, MDMA, DMT, etc. You can have a bad trip on any of them, I've seen weed freak people out a few times and a couple weeks ago I ate some mushrooms and thought I was going to fail all my finals, drop out of college, and that my life was hopeless. BUT instead of freaking out for 6 hours I managed to snap out of it a bit, went and chilled with some SOBER friends who calmed me down and despite it being one of the worst trips I've ever had I got it back under control after an hour or two of freaking out.
Just remember, when bad things happen and you're on drugs, its because you're on drugs.
I don't know what you were feeling while high, but if its having a lasting effect just take it as an interesting new insight - these things don't change you, you change yourself based on experiences you have while on them.