Symptoms: Out Of The Blue.... 3 Nights In A Month

Symptoms: Out of the blue.... 3 nights in a month I am waking up sweating and vomiting every 20 minutes for several hours and then must sleep the next day. I also find I'm belching more, things are sloshing around in my belly. I take a probiotic, I am a healthy 53 year old female and eat mostly vegan. Initially I thought it was a flu bug but after 3 nights in a month - out of the blue- always feel good when I go to bed and then it begins. Thank you for any insight you can give me.