non-lactational mastitis

So, I had my first ER visit last night. I'm 21 weeks pregnant and had not had sore breasts since week 13. Came home from work 2 days ago with my right breast hurting, and seemingly growing. I felt sick yesterday...flu like...so did not go to work but never really had a fever..had also taken Tylenol for the breast pain. I noticed my breast was red in several spots consistently, very feverish, and swollen, so called my obgyn. She said she had never had a case of mastitis in pregnancy, only during breast feeding, but I needed to be checked out Immediatly and get on antibiotics if needed. So, I did that. The ER was a nice experience actually, they gave me a breast ultrasound and confirmed mastitis, then started me on penicillin antibiotics. The pain is already lessening, just one day after.