Can Plan B make you skip a period?!!

Shannon

Took a plan b the day after intercourse around Sept 23. Had a period two weeks later (a full heavy period), then two weeks after that I had some weird spotting (brown) for about a week. Now my actually 2nd period after plan b is 12 days late. I’ve taken a pregnancy test it came back negative and I had a whole period! What’s going on?! Should I take another test? Should I call my doctor? Or just wait for my body to get back on track. Has this happened to anyone else before?!