Broken condom

Me and my boyfriend were having sex for the second time today when he went to go inside me about midway through and the condom broke. He had not ejaculated, and my app says I have about 1.4% chance of pregnancy. Should I take Plan B? I know how much it can mess up my body and do you think it’s likely that I will fall pregnant? Any comments will help. I’m being put on birth control on the 22 of this month so things like this won’t happen again. Thanks :)