Late period, negative tests

Alli

Has anyone experienced a missed period, had negative tests and still was pregnant? I've had blood work done and am waiting on the results as well as I have a sonogram scheduled for today, so I'll be finding out soon either way. But just curious if any woman has been pregnant with negative at home pregnancy tests? I'm worried for the worse case scenario

(Also I have NEVER missed a period by more than 2 days. I'm going on 20 days)