Pain during

Hi ladies! So I have been sexually active/masturbating for 15 years now and it seems I have a new problem as I can not remember experiencing this before. I was hoping for some advice/help. Im on my period, today is the first real day of flow. I tried to masturbate first by clitoral stimulation (I did use lube for both clitoral stimulation and insertion) and got off then when I inserted my vibrator I had horrible pain. I tried to push past the pain but couldnt. It hurt from the time I inserted the vibrator to the time I stopped. Does anyone have any ideas/advice?