Off pill 10 months ago

My husband and I have been trying to have a baby for 4 months now. I came off the pill around 10 months ago and have been using a condom until 4 months ago. I have always had an irregular period where it comes a week or 2 early. But sometimes I have 28-30 day cycle. While I was on the pill I had a 28 day cycle and since I have come off the pill I have carried on with the 28-30 day cycle but since we have started trying my period has come a week early twice and the other 2 times it was a 28-30 day cycle. This time round I started my period on 8th,finished on 15th, had sex on 17th, 19th, 21st, 24th but since the 21st my nipples have been erect and sore. This usually only happens to me 2-3 days before my period but not for every period. Could I be pregnant?