Effexor and 15 minutes

I went into full blown menopause 5 months ago. I could not sleep at nights, unbelievable hot flashes every 15 minutes throughout the day (I couldn't go anywhere without my hand-fan), crying over the silliest things, thinking people were purposely being unkind or cruel to me, - the entire situation was a nightmare to say the least. My doctor put me on Effexor and within 2 weeks, all symptoms (above) had completely dissapeard. It is the first time in my life I feel balanced and normal (even better than before I went into menopause). The only side effect I have experienced is that I cannot lose weight - I have not gained any, but seem to be remaining at the weight I was before going on Effexor.