Light period after plan B

[sarah ashton]

Almost exactly a month ago I took plan b to help ease my mind more than anything else. I'm on the pill but it was my off week and the condom broke but he didn't finish. Because I'm crazy I took plan b, however, I'm on my period now and it's been pretty light. I took a pregnancy test a day before my period and it was negative. Should I be concerned? I have been fairly stressed / working a lot too. Thanks for your help.