I took a plan B (on April 18) 3 Days after I got off my period (on the April 15) my period always last 7 days ..

For the 1st week after there's was a little spotting. Now during the second week I've been bleeding every day for the past 3 days.... .. should I go to the doctors? This is my first time taking one. Am I going to get my period on the in 3 days which is the 8th or is this my period?