Late period 2 months after plan b? Condom broke during intercourse

I took plan b in December, got my period twice in that month then in January I got a regular period but I don't remember what day it was, I also got a regular period February the 13, and since I got it last month on the 13th I thought my period this month would come on the 13th or 14th but it's now the 18th and still no period. My boyfriend and I had sex about 2 weeks ago and the condom broke, he ejaculted into it but I hesitated taking plan b again. So now I'm left thinking that I could be pregnant, my question is, is it normal that my period is late since I took plan b in December, should I still expect it to be irregular still? Or does this sound like I'm pregna