Chances of pregnancy??

Because of my irregular period it took us three tries before ending up with my first baby girl. Which I thought was pretty good. Now. After having her my periods became more irregular. Like not having a period for two months and then not having it for a month, stuff like that. Me not paying attention, we had sex on both days where my ovulation was at the highest according to eve, and he came in me both times. With my period being irregular which means my ovulation is off as well, how accurate do you believe it is and if I should be on the look out for pregnancy possibility?