No periods since 1st baby?

Not sure how common this is, but our daughter is 7 months old and I haven’t had a period since before I got pregnant. I am breastfeeding which is I know can be related and am cutting back a bit. We had a lot of trouble getting pregnant the first time due to husband’s lack of sperm but ended up pregnant at our appointment to start IVF. At that time, I looked ok but had low amount of eggs. Trying to make an appointment with an OB/GYN but they are making it difficult unless I’m already pregnant. Has this happened to anyone else? Should I just go straight to an infertility doc?

Thanks for any advice!!