Spotting a week after plan b. am i pregnant?

Preg: anything is possible. But more likely from the added hormones from the Plan B pill

Possible: The bleeding might be related to the use of plan B or early implantation bleeding. Would start checking a pregnancy test here in a few days and probably time to see your family doc or a gyn about getting on birth control so you don't have to take plan B

Possible: You can do a pregnancy test about 16 days after the unprotected sex - if negative by then you can relax.