morning after pill.

Me and my boyfriend made love tonight. I was riding him and noticed that the condom was coming off a little bit when I got off of him for a second. We put it back in and kept going for a little then quickly realized that it wasn't on anymore. We looked everywhere, and thought that one of us was hiding it as a joke. It was nowhere to be found so we decided to check inside of me. we checked twice the first time he didn't feel anything and the second time he reached in my vagina a little deeper and pulled it out. He didn't cum, nor feel like cuming. Do you think plan b would be a good idea to take?