Pneumonia

We have a 3wk old boxer puppie that's been doing pretty well,but yesterday we tried transitioning from goat's milk to more solid food(oatmeal+milk). She started fine but then we noticed she kind of started getting it in her nose because she was kind of blowing her nose out alot. So then we went back the bottle and now today she seemed kind of congested whenever we fed her the milk.
I don't know what it was but whenever I go on things like boxer forums they usually tell you to run to the vet for every little thing. In my experience I've noticed these people don't usually acknowledge alternatives because they don't seem to know how to address most health issues. But I do..in people.
One of the things they said was to make sure there was no milk in the lungs because that can lead to fatal pneumonia,for which I asked what will the vet do and basically they just said antibiotics.
My question is,since I can't keep affording the vet,is there anything I could do at home equivalent to the antibiotics for a puppy? Like I said I handle most medical things at home for humans.