Freaking out! Help!

I take the BC that has 4 sugar pills at the end of the pack. ALWAYS by the 3rd day, I start my period. I have taken this same kind for a few years total and started it back up in July. My periods have still always followed that pattern. Never missed. Always starts on the 3rd day.. Well today is the 5th day and I still haven’t started. I haven’t missed a pill other than one and these specific pills don’t cancel out after one missed day (at least that’s what the insert says).

Has anyone ever had this happen?

Thursday I had a weird feeling so I bought a $1 test and took it and it was negative, but the same thing happened with my son too. 3 days after a negative, I got a positive.

Obviously I was on BC cause we aren’t quite ready for #2 yet since I am currently job hunting, I need to make sure I can have maternity leave first. 🙈🙈🙈🙈