This is what happens EVERY night after about two hours of sleep, no matter when exactly I get to bed: I start to dream very intensely and coherently being very clear - not knowing it is a dream but apparently free in thinking and action. This gets on a while until I wake up with a rapidly beating heart (stays for about 30 minutes), cloudy vision and dream elements that are visible with open eyes, like animals, abstract symbols, humanlike faces, etc. Those are not related to the preceding dream content at all. After that I can not fall asleep again for 1 to 2 hours, no matter what I do. That happens only once per day and I experience this several months already.

I'd like to hear anything you can say about it.