Clueless

I had sex a few weeks ago, no condom. I'm on the pill and missed one a week and a half before. The directions say that for a week after missing my pill I should use a condom, well after the week was up the guy and I had sex without one. However I've been experiencing a lot of brown discharge and headaches. I've been very stressed out and I missed a pill after having sex. I also have been smoking weed a lot recently. SOS.