Antibiotics

I am 23 weeks pregnant and I have a tooth infection in a tooth that had a root canal done 1 yr ago. Went to Dentist and he won't pull the tooth till Dec27th and he did put me on antibiotics well within 24 I went into shock and my face was all swollen on the right side and red and hot. I went to ER and they put me on another antibiotic and now the same symptoms are coming up! Has anyone ever experienced this while pregnant? Their body rejecting antibiotics while pregnant? I have never ha any issues in the past and just was curious. Thank you!