I totally messed up! Please help!!!

I had a few drinks last night and hubs and I started to "dance." He also had a few drinks and wasn't able to make it more than 3 mins before he couldn't preform, alcoholisnt his friend (maybe a good thing in this case). However; he forgot a condom and I didn't even think of it after months of not worrying about it and only "dancing" once before in the months since birth. I woke this morning and immediately realized our error and though he didn't even come close to finishing I ran out and grabbed Plan B and started the ring. Called my OB and that's all the advice he gave.

I'm freaking out! Im in the process of weaning and spacing out feedings so LAM isn't exactly reliable. We are done having babies and I can't stomach having another so close or another at all. Husband has an appointment to get snipped so I didn't get on BC prior to this with the worry of hormones in milk and a plan to use condoms, and really...new baby meant dancing wasn't going to be on the docket for a while. I'm freaking out and this 2 week wait is going to be worse than when we wanted to get pregnant, I'm sick to my stomach with worry!! We can't afford 3 kids in daycare and we can't afford for me to stay home. So many bad words in my mind and I keep kicking myself!

Anyone else goof like this after their March baby and take the EC pill? How did it turn out?