Fall asleep for a few minutes before bed, go to sleep, wake up, go back to sleep - VIVID DREAMS!

[SuperFob]

There's this weird thing that happens. Sometimes, it's like an hour or so before bed. I haven't taken any naps or anything during the day. But, I'll sort of fall asleep for a few minutes some time during this hour before bed. I say "sort of" because I'm not sure what happens. Sleep seems to be the obvious thing, but this somehow seems different. I'll be sitting somewhere, then randomly wake up without realizing I ever fell asleep. I realize that I accidentally fell asleep for a few minutes. It's like a brief blackout, like I fell unconscious for a few minutes. I know it's sleep related because I'm always sleepy and struggling to stay awake when it happens, but it feels different than sleep. Was it sleep? Then I actually go to sleep for the night. But I don't make it very far. About an hour or an hour and a half into it, I'll wake up from a VERY vivid and VERY weird and VERY disturbing/unpleasant dream. Also, I'll remember 2 or 3 (maybe just 2) dreams from that one hour and a half alone. I think they seem pretty short, but there will have been more than one of them. The one I wake up from is always more vivid than the other one (or two) I remember. Normally, it seems like barely any dreaming goes on during this first hour and a half of sleep. That's what makes this all so weird. It seems like that brief, accidental bit of sleep I have right before bed is what induces the super vivid dreaming. But I don't know how. Does anyone have a clue what's going on here? I know all about people waking up in the middle of the night and going back to sleep in order to get more vivid dreams. It happens to me often. And it doesn't seem to explain what I'm talking about here. The dreams I get when the weird thing I described in this post happens are MUCH different and MUCH more vivid than what I get from the routine waking up and going back to sleep thing. Also, this occurence appears to give me EXTRA Rem periods when it happens.