Not sure what to do!

I took a Plan B pill in September, and my period came a couple weeks early which is a side effect that's stated on the information sheet. I haven't had my period yet this month(my last one was October 7th. So this new one should've started around the 9th or 10th. So now I'm around 10-11 days late. I took a pregnancy test just a few days ago, and it was negative. I've been having really bad mood swings, my breasts are starting to hurt, and this usually happens before I get my period. before the pill, my period would start the last week of every month. so I really don't know what I should be expecting right now! advice is highly appreciated!!