I am 16 i have had three periods in the last month i did have sex almost two months ago. But i have had tests and i am not pregnant they came back negative. I am having very heavy periods and i have to change at least 5 pads in the day. I have been having back pain very bad also very badly in my shoulders and neck. I get stomach cramps. Ive puked several times in the mornings. I have been on the bathroom a lot more. I have bowel issues and when i am ablw to go it hurts. I have also been sleeping a lot more. Im getting a lot more of the pregnancy symptoms two months later. What could be going on? Could i be pregnant?