i am 18 years old around monday morning i noticed a brown stain on Tuesday it got darker then wednsday i saw a spot of red and i though that it was my period staring but now its thursday and its still brown almost black and its not my period or atleast i dont think it is. its more like a discharge. i had unprotected sex a week or two after i had my period last month and my period is suppose to start about next week i also have been under a LOT of stress. so should i be worried or is it normal?