Help!!!

I'm posting as anonymous because I am embarrassed. So I just gave birth to my baby three weeks ago. Tonight my fiancée and I tried anal for the first time because he's been wanting to try it really badly but also because we can't use my vagina for another three weeks. Well we did it and he came in my butt, but then it leaked in my vagina. I'm freaking out. I just made him go get plan B just in case but they're not open. I'm scared it won't work because I'm considered overweight since I just had a baby. 5'3 and 176pounds. I'm freaking out!! I pump, can the plan B affect the breast milk? Do you think I'll get pregnant??  I'm so embarrassed to call my doctor or tell anyone. Please no negative comments. Just freaking out and need some comfort to ease my mind