Headache, cramping, sore breast

I have been off the pill for a few months now and my cycle seems to be 31 days, I have bought ovulation kits to help determine my ovulation day, which was meant to be happening , 24-36hours from friday. if today i feel slight nausea, headache , heavy breasts and movement happening in my lower area, is this telling me that ovulation is happening or that it has past? if you can advise thanks