Random bleeding?

Ok so me and my boyfriend are trying to get pregnant. Sunday started my fertility period, so we had sex, and we had sex saturday and Sunday. Today I randomly started bleeding. I'm not due for my period for a good 2 weeks? What is this random bleeding? It's not a lot it's very light. But it started this morning and has continued all day. Could this be implantation bleeding? What do you guys think? Help please!!!