Can plan b cause me to miss my period completly ?

Maybe: Usually Plan B induces a period early. If you haven't started you should take a pregnancy test.

Sure, other possibilities.: It is very common to miss, and certainly causes irregular timing of the periods a week or so early to two or three weeks late is very common.. With Plan B being used whether you interrupted a pregnancy or not. It is most likely that you're not pregnant especially if tests are negative. But act as though you are for safety and recheck in a couple weeks. Continue to use pregnancy prevention.