Could ive gotten pregnant?

Ok well I'm 21 I'm a mommy to a 6yrs old little boy. I've been trying to get pregnant for 2yrs now my period is irregular. I started my period on june1st2011 I got possitive ovulation on june 18th2011 I had sex on june20th2011 he did *** in me now we're wondering if I got pregnant... we had a hard time doing it during fertile cause our son was home lol but he finally went to grandmas on the 20th then we went to work so we only did it once... could I've gotten pregnant?