What Causes Spotting With No Periods After C-section?

hi i had a c section one month ago ive started spotting very litte not enough to were i have to use a pad... i havent yet started my period idk if that is normal? my husband and i have been having intercourse and he have camed inside me us thinking i cant get pregnant again.. yha i know dumb thing to think... now idk if i can be pregnant again or whats causing the spotting.