Sotoday at school, our P.E. class was running bleachers. I am usually fine after running, just normal heavy breathing, but today, i felt a really bad pain to the stomach. I had some water and we walked back into the gym. I didn't feel so good while walking there. So after we arrived I sat down for around five minutes and the pain faded away. So today afternoon, I went home and to the restrrom finding some blood on my panties. It wasn't heavy blood at all, like my normal period. At first I did thought it was my period, but then, up to now, there is no blood at all. I've checked too. Im really getting worried about why I bleeded. Can anyone help out? And if you think I'm pregant, I am 100% not.