Ovulation Ultrasound

Hi all, I was wondering if anyone can shed some light on an ultrasound I had done today? I am breastfeeding and have not had n cycle since falling pregnant. This morning I went for my yearly check up at the OBGYN and she pointed out an egg on the internal ultrasound. It was a round black area on the ultrasound. Does this mean that I am ovulating? How would it loom on an ultrasound if I am ovulating? If I am, is the egg fertile, or is it past the point of being able to be fertilized?