Irregular cycles postpartum

I am currently 4.5 months postpartum and 2.5 months post-breastfeeding. I have had 3 bleeding episodes since the birth. One 3 weeks after stopping breastfeeding, one 2 weeks after that, and one 26 days after that. My last cycle (26 days) was ovulatory confirmed by BBT and OPK. This cycle I am on day 18 with no sign of ovulation (only 2 OPK's that showed test lines 50% as dark as the control and now completely negative). I know that it is normal to have irregular cycles postpartum when ovulation has not been re-established but what about when it is? Should I contact my physician or not worry about this? How long after stopping breastfeeding should cycles be irregular like this?

I had normal regular cycles (30-35 days) before starting oral contraceptives. However, when I stopped them I went 6 months without a period but then found out I was 4 weeks pregnant (natural conception). The pregnancy was normal without complications. I never re-established menstrual cycles after stopping oral contraceptives. This is obviously why I am concerned about this. Thank you for your time.