Spotting

I have been TTC for a little over 2 months now and my period isn't due until the 10th. I've been taking OPKs since the end of my period because I really am not sure when I will ovulate. They have all been negative but I have been taking them with my first urine in the morning. (I found out also that isn't the best practice). Previously I was on BC and prior to that I had the Implanon in my arm. So this morning I was feeling a little cramping and then when I was in class (college) I had a little spotting. Has anyone had experience like mine?