I don't nap, but I often wake up after like three hours and think I slept for 15 hours and missed a day?? And we don't even have the AM/PM system here???
Because of my sleep schedule being all over the place I never really know when I wake up, so I always check my phone, cause I don't trust myself to just "nap" and if I nap with my alarm off I often won't wake up when I need to go somewhere like work. So I try to always keep my alarm on just in case, cause my naps can be anywhere from a few minutes to several hours, they get out of control, especially when I'm not feeling well.
I usually take two naps a day, one to and one from college. I and my boyfriend have become used to this that it's become part of our sleep schedule and even if we weren't feeling tired before we'll get very sleepy around those times so I think our bodies are used to it by now. I do very rarely wake up from a nap feeling very sick and like I'm in a completely different universe entirely though, I hate it.
One time, it wasn't a nap, but one time when I was staying over at a family friend's house I woke up on the couch and didn't know where I was for a good 15 minutes, it was a new house and I guess because I go over there late at night the living room looked completely different so I was like really scared for a while and then I got up and was like, sneaking around trying to find out where I was, got into the kitchen and saw pictures of them and I was like OH! it was the weirdest experience ever tbh.