Female rat needs help asap

Question
I have a female rat about 3 years old who came down with a respiratory infection about a month ago. I have had rats for about 5 years now and needless to say they are my life. I have seen many illnesses come and go and I have had a few rats come and go, God rest their little souls. Back to my question, when my girl got sick I started some tetracycline. I saw improvement, but then she seemed like she started going back down hill again. So I started back with the tetracycline with some amoxicillin for any secondary infection. Within the last week, she has gotten much worse, lost some weight, and when she "tries"to eat, and when I give her meds, she is doing something I've never seen before. She will take food and spit it out and rub her chin on anything and everything in site. She does this when I give her medicine also. She is not doing it in a way like its scent marking, but like there is something wrong and she can't eat or take meds properly. Again, I've never seen this before. I would have already had her to a vet but my other female just had surgery and the costs was double what the "high" end was supposed to be. Please help me, any advice would be greatly appreciated. I have done so much research, but nothing giving me an idea as to what going on with the chin rubbing.

Thanks in advance,
Carmen

Answer
Hi Carmen, I apologize for not answering sooner but I have been ill.  I have read Debbie's responses to the same question you also sent to her.  I also wanted to say I am very sorry you were not able to save your girl.  She did live a very long life and I sense that you provide the very best for her.  

Seeing that you are a long-time and dedicated rat owner, you probably already know this from your experiences with illness and death in your past rats, but I notice Debbie did not touch on this in her response, so I will bring it up here.  Again, you may already know this but rats, by nature as prey, have a tendency to hide very well any signs of illness and by the time you start to see signs, action has to be taken very quickly with medication because they go downhill very fast.  In nearly all cases, a rat who has stopped eating and drinking is usually fairly close to death and at that point, the best you can do is provide comfort.  

Treasure your times with your rats and cherish the memories of those that have gone.  Their lives on this earth are far too short.