When to go to the doctor? Late period and neg tests

Kara • RN from Maine, Married ♡. Momma to my little beauty 💕
I'm currently 5 1/2 weeks late. Ive taken multiple tests, all negative. Supposed to have started November 9th.. I came off the pill in September, had a period October 11th - October 18th (which was technically 2 weeks late) and haven't had one since. I've been told it's normal for it to be irregular after stopping the pill but when should I be concerned? Thanks for any input!