Plan B or no?

Hello so I had sex yesterday and I made sure that the condom was tight and everything, but when he pulled out the condom was a littttlle loose and he immediately started precumming/ cumming. I'm paranoid that since it was looser than before that some potential babies escaped the condom lol, but perhaps it became loose because of the friction of pulling out? According to this app I'm in my Fertile Period so I'm extremely paranoid. I prefer not to take plan B because I have extreme anxiety and the side effects will make my anxiety even worse. Opinions?