5 Days late after Plan B

I took a plan B on January 15th and had bleeding from the 19th to the 22nd (not my period). I was supposed to start my period on the 6th and it’s the 11th. Could I be pregnant? Or did the Plan B mess up my period?

edit: when should I take a test? It’s been 3 weeks and 6 days since the 15th.