Sensitivity Breast

Me and my boyfriend is trying for a baby. We always have sex unprotected. But we use the pull out method. This time on July 23rd, we decided not to and I let him cum inside of me. My expected period is not until July 31st... but when I was in the shower today and the water hit my breast is felt sensitive. Like a sore feeling. Could I have the symptom of my breasts feeling sore already? Or is that a possibility of me being pregnant? Or is there a possibility I've conceived?... I know I will really have to wait to see if I had a missed period. My last period was July 7 (5 days) - but I just want to hear other opinions, it would be highly appreciated !! Thank you.