Hi, I'm A Bit Concern On Dark Spot Most Likely

Hi,

I'm a bit concern on dark spot most likely looks like pre-period blood discharge everytime after i had intensive exercise(futsal/indoor soccer). I went to check with the doctor and scanned my ovary, kidney and uterus but everything is normal. I have no problem with peeing etc. but sometimes i feel weird on the lower part of the tummy. what could it be? is it normal? i fell down very hard on my left side of the body last year. would that be the reason?