I would definitely get that checked out by a vet. It sounds a lot like narcolepsy. I would get it checked out by a vet for piece of mind even if he says it isn’t narcolepsy.
As I read through your post I thought about narcolepsy as well. I don’t know too much about it but it... but it really seems like narcolepsy.
I grabbed her halter and yanked her head up before she would actually fall. She woke up for just one moment before she slept again. Of course I’m fine with her sleeping, so I let her do it again. (This whole time I was talking to someone so I wasn’t necessarily paying full attention to her). So she falls asleep and her head starts to lower a lot until it’s just the cross ties holding her head up. Then one of her legs bends and then the other and, again, she almost falls over but I grab her halter and yank her up. This happened probably 7 or 8 times in only about 10-15 minutes. Why would this be happening? Should I be worried about narcolepsy or was she just very tired? She does get cuts on her legs from this happening at night, so I know this isn’t the first time it’s happened.
This is a video from YouTube and it is exactly what happened to my horse! I know people in the comments of the video were saying sleep deprivation? My mare seems to sleep all day. If she’s not getting ridden she would be sleeping. Even if you halt she will be asleep in 5 seconds.