welcome to hcm
thanks for the query
as you mentioned your weight is in normal range
so no need to worry
just continue to maintain it
have good balanced diet with regular exercise .
do regular exercise
you can take multivitamns like vit b complex.
. your period problem may be due to primolut n
you can consult your gynecologist for other possible cause
you can also go for a pregnancy
test if you have unprotected sexual relationship with your partner