Not getting my period but not pregnant?

Help!! It’s been over 7 weeks since my last period and I’m not pregnant-I’ve taken 3 tests, once every week the past 3 weeks. My husband and I have been trying to conceive for 7 months now( I got my IUD removed in May) and my period has always been irregular, but usually it will be a 4.5-5.5 week cycle. I’m 23, average weight, never been pregnant before, and none of my female family members have had problems trying to conceive(I have two uncles who have had issues with infertility).

Does anyone know what could possibly be going on with my body or have experienced something similar?