rather than bliindly guess at a reason i would strongly suggest that you see a gyn specialist to determine the cause. this is not "normal" so you deserve a careful diagnostic work-up.
i stopped having periods at age 37 (5yrs ago). i started a period 7 days ago. very heavy. is this normal? . this period is very painful and the blood is bright red. i have hep c w/cirohsiss (sp? ) and my platelets are usually on the low side. could this be the reason for the bright red color?