Scared of unwanted pregnancy. Doctor?

Hello doctors, My last period came on 29th august and i generally have an irregular cycle of 28 -32 days fluctuating every month. I had a proper protected sex on 10th sept using proper condom and wiping off immediately with water despite using condom. By the cervical mucus i felt my ovulation started from 11th and on 23rd and 24 sept i felt 2-3 seconds of cramps in my abdomen just once and it was gone immediately. According to the 28 day cycle my period is due on the 27th sept.. And based on the 30 day cycle it is due on 29 sept. I don't feel any other thing just a little bit of mouth dryness or tasteless and along with that today i feel my back is becoming heavy as it feels before period. I don't feel any nausea and dizziness, nor do i feel any other cramps other than the one i mentioned above just for 2-3 seconds. Do i need to worry about my pregnancy or is it just PMS symptoms. Please I'm really scared of it. Doctor