Is it normal that i often have those "illusions"?

So I have these dreams, if you want to call it so. I'm someone who isn't able to sleep so well and I wake up every 2 or 3 hours the night if I'm actually sleeping. I spend much time to be half awake, so not really sleeping but not really awake as well. If I'm in this state I'm used to imagine my teachers asking me random questions like "What is the content of this paragraph?" or something. Not being in my room but nah anywhere in my imagination in the dark. And right after these teachers asked their question I want to put my hand up but I'm pretty unsure about it because the thing I want to say might be wrong. During this thinking I also make sounds like, you know, "eeehmmm, hmmm.. what could it be?" (and really saying it). I just decide to put my hand up (and I really do with my arm in the reality) but after the teacher has chosen me to say something I forget what I wanted to say and hestitate a long time before realising that I was half awake again and just imagined it. I remember the images I saw while I was half awake like feeling uncomfortable and moving from side to side. After this strange happening I just try to sleep again. I have to say that I go to school from 8am until 4pm and also spend much time doing homework. Is it just a reaction to stress? Because this just occurs in certain periods and then it disappears again.