Telling the dad?

So I've only been dating my bf for two months, we've known each other for two years and decided to get start something. We have had sex already, but don't say I love you, because we both know we don't. I told him that I missed my pills and he flipped out past high heavens, I'm pretty sure I'm pregnant, and so I don't know how to tell me, how and when should I tell him.