Excessive timed hotflashes

Hi everyone. I had a partial hysterectomy 5 years ago. My ovaries have decided it's time to start shutting down. I have a hotflash every 20 minutes. My doctor today treated me as if I was exaggerating. I showed where I timed them and was told 30-40 a week is severe. What the heck is happening to me? I have more than that in a day and they are timed. How hat can cause the body to time them so precisely and over the top often? Sleep deprivation is starting to kick my but. It's 24/7

Thanks