The crocodile dream sounds like fun. Odd thing - I dreamed this morning that I was playing the Hallelujah Chorus in an orchestra, using a wooden flute. Maybe the Hallelujah Chorus is circling the globe in subsonic form.

Are you drinking any alcohol? A glass of wine with dinner, a martini before? A small amount of alcohol can really affect some people.

How about ambient noise? Are you hearing roofers or road workers (etc) whose noise in interpreted by your brain as something else?

Most vivid dreams come as we are about to wake up. You have my sympathy over the dream that made you wake up sweating. I have those dreams once in a while, and they are no fun.