I would say its the menopause. I get hot flushes that wake me up in the night, and hot flushes that leave me drenched in sweat throughout the day. My clothes stick to me, feels like I need to have a shower and get changed.
They make me feel slightly unwell till they past.
My doctor is not keen on prescribing HRT, but then again some doctors are keen. Both my sisters took HRT and felt much better.
I think HRT is safe it has been used for many years now, you should have a chat with your doctor.