I went through instant menopause when I was 44 (maybe 43?) Anyway, total hystorectomy including ovaries. OMG!!! I was not prepared for that! Hot flashes like you wouldn't believe for at least a year! I swear a person could see steam coming off me. It was very embarrassing at work... in a meeting and suddenly my face is running with sweat.
It was heck trying to sleep. One moment cold, the next so hot I couldn't stand it. I had to have a fan blowing right on me. When I wasn't having a hot flash I was bundled up in the covers, then the next moment throwing them off and cooling down in the fan that a minute before was freezing me.
It passes, though it doesn't seem like it will. It's been a few years since surgery and things are settled down now. :D