Please see your doctor as soon as possible for reassurance. Not only because of the possible pregnancy, but also other issues that could be far worse. By all means, please be more careful from now on if you don't want to take the responsiblity of the consequences of a few minutes of pleasure. Your b/f, in my opinion, should get more educated and start respecting you more as it will also change his life.
Wishing you lots of luck, and please keep us posted.

Am enclosing a document that might be of interest to you and your friends, so please share it.