I stopped having my period approximately a year ago but it started on friday again. it happens every 6-9 months. is this normal?

Abnormal bleeding: Since you are having bleeding that is irregular and you are in the perimenopausal period, it is difficult to assess if this bleeding is normal or abnormal. The best course of action would be to see your doctor to help assess this. It can be functional bleeding but it also can be from precancerous changes in the lining of your uterus that can be easily evaluated by an endometrial biopsy.