Spotting after sex during Ovulation...

We got our solid smilie on Thursday morning after we had BD (this was also the day we had our first appointment at the Infertility office). Doctor said to try go ahead and keep trying and to be active yesterday and today. Each time after when I went to the restroom there was some pink/light red spotting in the toilet paper. The spotting stops pretty quickly, but wondering if anyone had had this before? We had been trying since CD10 and no spotting till positive ovulation on CD14.