plan b opinions?

Okay so i had protected sex with my boyfriend June 1 but the condom broke. I took a plan B less than an hour later. June 9 i started spotting and had a very very light period until June 13. My normal period is heavy flow and normally 25-30. Im 99% sure this bleeding is the plan b working, but i've read so much different stuff that i just want opinions to see if others think it's working too.