I've never had this happen before my periods are regular. My boyfriend and I had unprotected sex on the 30th of Nov  & 1st Dec. And on the 5th day I spotted for three days then went light n came back so as of today I been spotting since then. My regular period starts about 22nd. Could that me implantation bleeding. I took test week ago came out negative, not sure if that was to soon. Any advice will help. Thank you