I've taken plan b before and I don't usually bleed after taking it and it doesn't usually delay my period. But thank you.
You are probably not pregnant. If you took the plan B right after, didn't that make you bleed? When I did, I promptly had very heavy bleeding, and then no period again until about a month later, so it basically brings on an early period.
If you had no bleeding at all, even after taking plan B, I'd go see a doc, honestly. I still think it's not likely that you're pregnant, but that seems odd to me.