We ended up having to let her go. Her pneumonia was worsening, she could barely breathe even with oxygen, and antibiotics *might* have helped i decided not to let her suffer on a crapshoot. The vet didn't charge for new xrays but we did have to pay for euthanasia, so we could still really use help.
Our other cat (not the one who was so sick a couple months ago) was dry-heaving yesterday and this morning she doesn't want breakfast. She's gotta go to the vet and we absolutely do not have budget for it. If anyone can help, paypal.me/utilitarienne