plan b information

So yesterday around 430pm this guy and i whom i have been hooking up with for a month or so, had sex without a condom on. I'm on birth control but we not sure where excatly he came and due to that my nurse friend told me to take the 'take action'-plan b pill. I'm not ready for a child at all and I need some advice or reason to stop thinking that. It might sounds nuts but I suffer from anxiety attacks and my last period was spotty and horrible pains because I couldn't calm myself down. But I should be good right?