Help please !!

My son is 15 months old and still breastfed. AF has finally made an appearence on May 25, still bleeding lightly. My cycles were pretty normal prior to first pregnancy. However as I am still nursing and new to the whole TTC, what is the best way to determine if I am indeed ovulating and when, or if AF is without ovulatuon as we a nursing. Any tips and info appreciated, thanks.