I have been with my bf for almost three years now. I have an irregular period, Sometimes i get it one day and then the next time around it takes a little longer or comes sooner, so due to this I dont keep track! I am currently 27 weeks and 4 days. Due January 30,2017. I have a big issue though! Me and my bf had unprotected sex without the pullout method on May 8th. After May 8th, I think we had unprotected sex a few more times and he might have came in me again. On May 14 or May 15, We got in an argument and broke up which led me to having a one night stand on around May 16th or so. We used protection. But first condom broke then he changed it and came in the second condom. I am not sure of when my Lmp was, but according to doctor it was April 25th. I am most certain it is my bf whose the Father, but i have been overthinking it and stressing about it. Can someone help? Im pretty sure since the one nighy stand didnt cum inside me he isnt the father, i just need some reassurance. Not proud of this at all!! Also is there anyway, my due date can change? Since most ultrasound aren't accurate on gestational age of fetus. 

Your help would be highly appreciated!