My baby was doing the exact same thing, after scaring myself to death searching Google I took her to see the vet. she said they are very good at fighting the infection off as long as she is kept warm, carry on bathing as usual and just keep an eye on her. She advised if it carried on after 3-4 weeks to take her back and they would look at finding am antibiotic dose for her. Touch wood I haven't observed her doing it over the last week so fingers crossed she has fought it off. The vet explained they were quite like us with antibiotics and if started too young they can become immune!