duration of menstruation cycle fluctuates..from 2 to 5 days..pain ,heaviness in lower area during dis period is quite normal.. unless c has got fever,burning micturition which needs to evaluated furthur. fr nw if heaviness is troublesm ask hr to take tab diclofenac 100 mg 8 hrly till its dere periods r greatly affected by mental stress and odr physiological parameters like anaemia n all. so i wud like u to advise nt to give hr such stress by any means u need to take care of hr during this also aftr dat bt extra care here.