Trying to convince baby #3

Hi ladies. So I am still currently bf my daughter who is 15 months old. She maybe feeds about 3 times a day. We have been trying to convince these past 3 months but no luck, I got pregnant with my other two first time trying. I am getting positive opk each month and trying when needed but still no joy. Has anyone had the same situation or know if me breastfeeding is what is not getting me pregnant. Forgot to say AF came back at 11 months. Any advice would be great☺️ x