Late period advice

Leah

So last month while ovulating, me and my boyfriend did the deed. I am on the ortho-micronor mini-pill, but that day I had taken it irregularly and really late. The following morning, I took plan b just to be safe. As of today though, my period is two weeks late. I took a pregnancy test last night because I was nervous I was pregnant, but it came back negative. It has been a month since I’ve ovulated so I should have been able to find out by now if I was, and I used a reliable pregnancy test. I’m just curious to what could possibly be happening to my body. Yesterday I was spotting for only a few minutes in the morning but then I never got my period? If you have any advice or have been through something similar, I’d love to hear it. Thank you!