i dont know much about periods. im 21, never had them before up until my surgury. recently i started what i thought was my period, today is day 7, STILL heavy bleeding off and on, my stomach feels like someone is poking me with needles, my back HURTS so bad, i cant bend down. i used tampons at first but i switched to pads because i was changing it so much, i am filling them full. is this nornal? or should i be concerned? sorry if it sounds like a dumb question.