I am only 39yo in Early Menopause.
Chillijava is right in that it usually take 7-10 days to start to feel better.
What type of HRT are you on?
Sometimes it takes awhile of fine tuning to get to just the right dose and right kind that is right for you. There are so many different kinds of HRT.
I have been so exhausted so my dr. just changed me to Estratest. He swears that it is the best and that my energy level should increase dramatically.
Hope he's right!
Glasscrab-
If you go to the DR., they will probably test your estrodial and FSH levels. If you aren't having bad symptoms, you do not neccessarily need HRT. There are alot of OTC things you can take. With that in mind, make sure that you get the calcium that you need. I have been told that Early Menopause can increase your rate of bone loss leading to Osteoporosis. You should also get a bone scan done. My sister is only 45 and has horrible bone loss.
Hope this helps.