What causes spotting? I had it on the 5-6 then again on the 14-18 and( 25-28) started after intercourse It hasn't been…

What causes spotting? I had it on the 5-6 then again on the 14-18 and( 25-28) started after intercourse It hasn't been like a normal flow kinda period. Not even soaking pads or panty liners not cramping nothing..... could something be wrong with me?? Has this happend to anyone