Ovulation date for me...?

Ok so my periods since my husband and I have been trying are always all over the place. I never really know when I ovulate.... So this month I started my period on June 24th and it was the 26th day..... I dont always trust the babycenter and all those websites... And so i dont know when the luted phase is ?? Please help! So when will I ovulate... And i am having the HSG test done friday when should we try???