Missed period

brittney

I was suppose to start my period on September 20th and i haven’t yet. My mental health is so bad since having my daughter almost 9 months ago And the past month my anxiety has been at its worst. I’m so scared to be pregnant again can anyone give me insight as to why i haven’t started yet? I’ve had all the signs like I’m going to start but haven’t yet. I’ve already taken 3 tests and they’ve all been negative.