Stopping the Pill

I was on Lo Loestrin for 5 months and ended up stopping Oct 9th to switch to condoms. My first day off the pill was Oct 9th and that was the first day I was scheduled to start my period. Fast forward to this month and my period is now 6 days late. My husband and I did have unprotected sex once by mistake while I was ovulating. I don’t know if my late period is from my change in birth control or if I’m pregnant.

Also I forgot to include: To add to my confusion I have been increasingly nauseous, my nipples have become pretty tender, I’ve noticed I’ve gotten more and more sensitive to certain smells and a few more symptoms despite the pregnancy test I just took today that came back negative.