Tell your gp to take a running jump. What an *&^!! The very worst thing you could do now is slow down on feeding.
Ibuprofen all the way, and feeding. Hope the abx help. I had recurrent mastitis, it's an absolute killer, rest + ibuprofen + feeding is what kicked it in the end. BUT I fed my boy for 17 months and have done the same for my girl. It is so worth it.
Hugest hugs. (very gentle ones)