i had sex with two men in the same week who is the father?

I had sex with my ex boyfriend on January 13 a Sunday  we used a condom but it broke he did the pull out thing but im not sure if any sperm had went in, i used to think that this man could not get me pregnant because we tried the entire summer to conceive and i wasn't getting pregnant by him so there was a point when i started to think that he wasnt able to get me pregnant. so on a Thursday the 17th of January 2013 i had unprotected sex well u can say the Friday the 18th because it happened 2 am with another ex of mines without a condom he did not pull out at all he came all in my insides multiple times that early morning, the reason why i'm confused is because i'm pregnant now and do not know which one is the father, my period cycle is irregular so i cant even calculate my ovulation days, i really need help i just figure that maybe it cant be my first ex because he want able to get me pregnant before so why now especially when he actually did the pull out thing when before he never did that, please can i get some advice, thank you