Plan b 6 days ago. started spotting same day. light bleeding, old blood, ongoing (not norm). is this my period or is there still a risk of pregnancy?

Chances: are if Plan B was taken as directed and in timely fashion that you are not pregnant...you might want to take a Pregnancy test if your next period is delayed (just to be certain) Hope this is helpful Dr Z

Not uncommon: it is not uncommon to have some irregular bleeding after taking Plan B. It is important to do a follow up preg test in 2 weeks to assure it is negative