This month has been stressful. Me and my partner have had sex a couple of times, only thing is it wasn't for very long. Although there was mostly likely pre cum, he didn't fully cum/finish either of those times. I'm on the pill and have missed it twice this month but took it the very next morning. Now my nipples are sore but that could be because their still developing as I am only 17. I swear I feel aching in my lower stomach but that just could be me imagining it. My partner says I've been moody but that also could be the exhaustion from TAFE, work and school. 

Should I be worrying about the possibility of pregnancy or should I try and put my mind at ease?