How to tell when I should ovulate?

Hi! 2 years postpartum & had my IUD out on 01/12. Had sex the day before and day of as well as several times since. I bled heavy on 1/16 and 1/17 . Is that considered my period? How do I know when I am ovulating. Currently have watery discharge, back pain and cramping today. Took a pregnancy test and posted it but most said its a dye run. I had an ovulation test on 01/30 and it looked positive. I can post that too. Any ideas, help?