Neg test, late period?

I am ttc my second child. I have been keeping track of my cycles and I should have started my af yesterday. When I conceived the first time I didn't test positive until 2 weeks after my estimated af but my dates were completely wrong. My girl was not as far a long a I suspected. This time I have my cycle down pat. I tested yesterday and got a digital [-no] (wasn't morning urine) on a hpt. Tried today but test never worked. Idk what to think at this point. What are your thought? I've been trying for four months, which I know isn't that long. Just really want another beautiful baby.