My boyfriend and I are in college, and he's in a pretty intensive program, so he often stays up all night to get work done. Last night he did just that. When I woke up I asked him if he wanted to go get coffee, and despite his exhaustion he said yes, so I picked him up. As I drove I was talking about our weekend plans and how excited I was. He looked at me and said he couldn't hang out with me, he was hanging out with Joanna. Well that was weird, bc I am Joanna. A few minutes later he started asking where Joanna was, and when I said I was right here he looked at me like I was a total stranger. Then he started asking where he was and how he got there. I explained where we were and the put a hand on his shoulder and asked if he was ok. He replied with, "please don't touch me, I have a girlfriend" as if he had no idea I was his girlfriend. After about five minutes of this he snapped out of it and started talking to me as though nothing had happened. At first he didn't believe me when I said he hadn't recognized me.
Is this a normal symptom of sleep deprivation? Or should I be concerned it is something more serious?