Help! BFN but am I pregnant?

BreeAuna • Mama of 2 girls and #3 due Dec 2018 👧🏻👧🏼👶🏻❤️
Ladies! I need help. AF was due 12/15 but I have yet to see her. I had a miscarriage inSeptember  and have had two periods 30 days apart since then. I have taken several FRER and have only had BFN. Should I buy different tests? I'm so confused because I have never been late by more than one day. Thanks!!