Plan B... Emergency Contraceptive

I'm scared out of my mind! I had sex with someone that I shouldn't have! The condom ended up breaking and we didn't know until we finished! I bought the plan B pill right after and took it maybe an hour and a half to 2 hours after the situation... has anyone ever experienced the Plan B pill? Did it work for you? 
Please help! Freaking out!
I'm also on the last day of my period... 😖😖😖