Hello,
Spotting or after periods vaginal discharge is most often associated with old endometrial tissues. In other words, if your period is late you might get a brown, rather than red, discharge. It could also mean that for whatever reason during your last menses the entire uterine lining failed to make a timely exit. In some cases however there is cause for concern and then it needs evaluation if it persists.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Was the sex just a little rough or a lot? Did you have rough sex with him before and didnt experience pain and bleeding?