Peri-menopause can start at any age, and your symptoms sure to point to it, just because the lab work
does not show it,
does not
mean you are not entering it. The lab work is only a picture of what is going on for that moment. Have you had the saliva test, this is very accurate and tests for all the hormones, I would certainly ask for you if you have not had one.
Endometritis can also be another cause for the heavy bleeding. Having a sonogram of the ovaries, etc, can tell if you have that.