Confused??

Okay so I went to the ob this past Friday and I started spotting yesterday. I started bleeding today but its light/medium... I think its my period but my period is supposed to come on Jan.1, I had recently took a plan b like on the 13th of this month. It stated it could make it come on early... But what im trying to make sure of is taking my birth control pills right. Not planning for a baby right now. So the doctor was telling me.

Example: Period comes on Monday she said wait until Sunday to take it so it will be easier to follow. ?

But it came on today for myself so do I take the pill tomorrow?? Or it's too soon wait until next cycle??