You should take Ginger to the vet ASAP and have her treated with a non-penicillin-based antibiotic (penicillin is toxic to cavies). I haven´t any experience with URI meds - perhaps someone else can suggest? (Baytril?)
Pigs go downhill very fast and it gives you very little time to react. At the top of this page, you´ll find a link to safe meds. Remember ALL penicillin products are toxic to pigs. Print that list and bring it with you to double check.
Do you have a vet? If not, you need one now, one that is experienced with guinea pigs.
Are your pigs eating ok? How old are they? How are they "acting funny"?