I am 21 years old. I had been having brown vaginal discharge (very little every day) for more than two weeks now. Now i am having watery discharge. I had sex for the first time in the middle of last month. I was supposed to get my period a few days later. However I did not get it then, but I might have been a little stressed out at that point of time. But since early this month, there has been some brown discharge and it is not at all like my normal period. It is very different in color and the amount is very very less. Also, I have taken two pregnancy tests, and both were negative. Should I be worried?