Spotting

So I have had spotting while I'm on the pill maybe twice now and I have never skipped a pill and I'm not suppose to get my period for another weekish. Me and my boyfriend have had unprotected sex but he always pulls out. I also accidentally forgot to take my pill Sunday night but took it right away Monday morning. I have been very stressed though, so I'm wondering if that could cause it too? What are the chances that I'm pregnant???