Health issues. And little tensed too.

Hi, I am sexually active with my boyfriend and i am having issues after having sex. After some days of intercourse, maybe after 2-3 days i bleed, but its not due to the periods. Also, I only bleed 3-4 drops of blood and then i do not bleed at all.. Which surely means its not my periods.. This is the second instance which i have experienced today.. I had the same experience when i had the intercourse the last time... Kindly assist me, is it a matter of concern.. If yes what shall be done in this case.. Shall i visit a gynaecologist or not.. I had urinary infection some while ago which later probably did affected my kidney as well, however the urine report didn't show any infection sign.. Also got a check for kidney stone, however it was nullified.. Kindly help me with further steps.. I am clueless and little tensed too.