Can Plan B Contraceptive Pill Cause Delayed Periods?

I took a Plan B emergency contraceptive pill 2 days before ovulation. I was due for my period on 1/7/15 and still haven't gotten it (5 days late so far) I've had every symptom, but no bleeding. Can I be pregnant? I've been reading that it can be up to one week late, but I'm getting nervous. I was going to wait a few more days. Could I be pregnant?