I've just had one. I haven't had one for a few years. I suffered with them back in 2017 and 2018, I must of had about 7 episodes back then. First one today since. I can't even describe it, I almost feel possessed like something else is taking control of my mind. I suddenly wake too, and don't feel tired just like something is taking over my mind and nervous system. It's very scary and I hate it.
If anyone else has had them what do you do to calm yourself down. I literally had to get up and pace around my house. It eventually wore off when I sat up back in bed. Nothing triggers them, I don't even need to have a dream it will just happen.