I was hearing all kinds of shit like sirens and people yelling and everything. I could barely walk at one point, I could not really speak clearly and I was seeing shit.
I couldn't speak very clearly for three weeks after my sixth high. Speech impediments can definitely be caused by weed.
I can relate to the sirens and the yelling. In my experience, the sirens start as electronic voices which repeat syllables really quickly (...plolololo... or ...flelelele...), then it turns into a weird flanging vacuum-type siren, then it becomes very space-age or turns into a civil-defence siren. After that come the panic attacks and crazy paranoia.
As for voices and yelling, as the dose increases I hear blurry echoing voice-like sounds, then they start repeating, then I can sometimes hear a distant voice spewing out nonsense (or an object will repeat something in a rapid, high-pitched voice), then the voices become interactive (or sometimes I can hear my own thoughts), then the real fun begins at higher doses, things like invisible forces pushing me around, voices taunting or threatening me, drills or saws, people screaming in pain, etc.
The stuff you smoked is most likely a strong Sativa-dominant strain, and that shit will make you trip if you smoke enough of it. I find psychedelic trips to be much smoother and way better overall. Tripping on Sativa is overkill and unpleasant IMO. That's not to say that you can't get intense moments of euphoria from it.
Sativa usually has a much higher trip ceiling.