PLEASE HELP!!!

Leah β€’ πŸŽ±πŸ’•8/16/2015πŸ’•πŸŽ±
Today me and my boyfriend had sex and he came in me. It is my most fertile week! I have a 33% chance of being pregnant. I when my to Walmart and got a plan b pill. How long should I wait to take it? Or should I not wait? Someone please fucking help me.Β