Plan b, late 2ed period

How many have had their 2ed period late from plan b? I still feel weird, but I don't think I'm pregnant. A few days after I took it I had spotting, and I believe turned into a light period. It would make me about 5 days early.

Now I haven't got my second period yet. I took two pregnancy test. Both came back negative. First one was about 5 days ago, and the other one was yesterday.

And if I was I would be just a few days past six weeks. Just wondering how many had a 2ed late period?