TMI: Brown Discharge

So my boyfriend and I have been getting more intimate with eachother... he's fingered and have gone down on me a couple times now and everytime I get home I go to the bathroom and I have this brown Discharge. It lasts like 3 days. Then we had sex and I bleed but it was more like the brown Discharge again... should I been nervous? I've had sex before and over the summer I had PID... please help