I get bouts of nausea every few months. Ever since I can remember, up until now (late teens) every few months, ranging from around every 3-6 months, i get bouts of nausea at night. I feel extremely exhausted, I'll often fall asleep for about an hour or so and then wake up thinking I'm going to be sick, I then sit up in bed trying to sleep, and when i do drift off it's usually for 10-30 minutes and I have extremely vivid thoughts and dreams, I also get really cold and sometimes I'll be sick and then fall asleep or other times i just sit up, frequently getting out of bed as i think I'm going to be sick, and just waiting until I eventually fall asleep. This usually happens when I've had a couple late nights or tiring days with late nights, or when I've eaten a lot of food during the day that I don't usually eat. Because I know these triggers it happens less frequently than it did when I was younger but it still happens every 6 months at least and I don't know what it is?