I Took A Plan B A Week Ago..however Had Unprotected

I took a plan b a week ago..however had unprotected sex the night before yesterday and several hours after sex I noticed spotting and my period started...I read a sperm can live inside a vagina up to 5-6 days until I become fertile whenever my period ends which is usually 5 days long...should I take another plan b to be on the safe side or would it be unnecessary?