That's called
hypnagogic imagery/hallucinacions. It's a state you enter between being awake and being fully asleep. It happens every single time that you fall asleep, but because you're not really conscious usually, you forget about it before you wake up next morning. It's perfectly normal.
What if you don't forget it? I was reading that article and it sounds exactly what happens to me a lot. I like get into this half dream thing where I trying to go to sleep but like I am dreaming, but not that much only like a half dream.. But it's like exactly like this "They are said to differ from dreams proper in that hypnagogic imagery is usually static and lacking in narrative content. from simple ‘eigenlicht’ to whole imagined scenes." For example I would feel or see my cat on the bed with me and suddenly it makes perfect sense that shes a general for some war or some shit complete with a little outfit (although I don't usually see it as a perfect solid thing), then I turn over and I'm like wtf was I thinking?
I dunno if it's hypnagogic or just everyone gets em.
oh yeah and what I originally came in here for. So when I came back from work today I couldn't sleep for shit all, so I decided to play some cod and jack off (AT THE SAME TIME) to see if it would help. So I fall asleep eventually but I wake up later because my moms bf was listening to his radio, so I get back into that half dream half awake state and every time I fall asleep I think that some jackass with a ump or scar is gonna rush in and kill me. So I'm tossing and turning, and everytime I start to get sleepier sure enough some asshole starts to come at me and I wake up again. This goes on for HOURS, and suffice to say I'm really ****ing tired right now.