Very late but negative tests??

My husband and I are TTC. Since getting off the pill in February I have been super regular. Last month I was 2 weeks late (yay!) but then my eriod finally showed up and lasted 9 days (fml!!)

This month I'm now over 2 weeks late again but home tests and blood test last week were all negative, and still no period or symptoms in sight!

Is it possible for the hcg to just be taking longer to show up? Should I test again? How long should I wait until I call the doctor about being so late? Help! :/