I took plan b about a week and half ago. And my period came 3 days earlier then it was supossed to. And I usually have normal 6 day periods but I'm on my third day and it started off heavy and now my period is super light. Could I be pregnant or could it

Plan b side effect. That is the plan b altering your period. It can make early or late, light or heavy bleeding. Why you think you could be pregnant? You are having your period. Having period means no pregnancy. If you are in doubt you can take a pregnancy test.