I had this with Jonathan, too. Actually, I think it was worse with him. It was always when I'd done a whole lot of work and I wasn't hydrated.
Since it is only a little spotting when I wipe (and not every time), he's not too concerned. He said if it got worse or if I started cramping, to call him. Take it easy. Increase liquids. Since I'm just coming off of a really big infection, I need to make sure I'm getting enough fluids since I didn't get much for over a week. And I just really haven't felt like eatin/drinking a lot this week either. I need to force myself to, whether I feel like it or not.