The average age to go through the menopause is 45-55, but taking HRT keeps levels of hormones artificially high. What then happens is that when you come off HRT the sudden lack of hormones produces hot flushes etc., especially if you are in your late 50s or over, when your own hormone production will have stopped (this happens on average between 45 and 55 years old). Also, coming off HRT suddenly is very stressful for the body, which increases the flushing. You could try Sage tablets to help with flushes and you may also find a general multi vitamin helpful too. Acupuncture can often work well when HRT has been withdrawn suddenly, so is worth looking into.