Implantation or period

For the past several months I have been regular and my period is always very heavy. We are trying to conceive and I started spotting on Thursday and its was very light through Friday. Yesterday and today have been a little bit more but not enough to fill a tampon. I'm just wearing a thin liner and it hasn't leaked through it. But when I wipe I get more than just a little spot. Any idea if this could be implanting bleeding or is it likely my period. Period was supposed to start tomorrow(monday).