How do I know if I have ovulated? (Positive tests, but BF)

SF • We have a 5 yo and it took about 4 years of trying for our 2nd, due in July.
I am 39 & DH and I have been TTC #2 for 8-9 months now. I am using the CBEM and getting peak days each month. No dice! I know plenty of women have been able to get pregnant while Breastfeeding, but my OB recommended I wean my LO if I was having trouble conceiving. 
​I have had the first round of infertility blood work done & all of tests were in the normal range. 
​My LO doesn't want to wean, but I can make it happen, I think. I just am wondering if it's preventing me from ovulating. If I'm not ovulating, could I still get peak days with the CBEFM?