What is going on!?

I am 11-12 ish days late for AF. Taken two tests and both looked negative (one may have had a faint line but it didn’t look to have any color to it). There is a definite chance I could be pregnant, but my husband and I haven’t exactly been trying, but also not been preventing (pullout and unprotected). My period is usually like clockwork and predictable. I am frustrated and anxious I have no idea what is going on. Anyone else have experience with this? Any advice?