if he used a condom correctly, then you will be fine. you were there and you could tell better than i could whether anything went wrong with the condom
also, if you are as paranoid as you say you are, then it's a good idea to STOP having sex. Why on earth would you continue to have sex if it would only cause you so much anxiety? Sex is supposed to feel good. Worrying and panicking over pregnancy scares everytime you have sex does not feel good.
If you are going to freak out every time you do it, even when you know you did things right, then I would strongly advise that you hold off on sex until you can gain the composure to not only be ready for the act itself, but be ready for any consequences, too. Which is not to say a girl doesn't become seriously alarmed if she's pregnant on accident, but she should be able to handle the situation calmly and rationally.
mundi faece repletum