oopsies happened

My SO and I had sex with condom and I've been on bc for two months and 1/2 a week (and I'm in my withdrawal days (period)  right now but I just started my new pack two days ago). The condom ripped... and now I'm worried bc I'm not sure if he cummed inside of me. He said he didn't but idk (it's not that I don't trust him or anything but right now I'm just at a complete high of anxiety so I'm mentally all over the place right now).  I'm freaking out and wondering if I should or could take plan b?