Urgent Question

[ryablue.livejournal.com]

So, I took plan B on the 12th May ~30 hours after unprotected sex. Had some bad cramping that night. On the 18th the condom broke and my period was due another week but 2 days later it started but it was really light and lasted for 5 days instead of the usual 6. Two days later I started spotting but only like two drops for two days.
I'm really confused at this point: could I be pregnant or is it the plan B messing up my cycle?