Thanks all. I had a long talk with a friend today. We talked about a lot of things, not just the dog. I feel a little better, now.
It's kidney failure. Right now, we have her on two different antibiotics, in case of Lymes or another bacterial infection, but the kidney values were so low and dropped so quickly that the damage to her kidneys is such that she won't have more than several months, apparently. She was a 14 pound dog, that is now just under 10. She's even lost weight just since Friday (just a few ounces, but on a 10 pound dog, that's a lot).
We are giving her Pepcid for the stomach issues.
The other treatment that we are doing is subcutaneous fluids. I have to stick a needle in the neck tissue and give her fluids twice a day. Apparently that did help, somewhat, today, because she came home and ate what she refused earlier this morning.
They only gave me three weeks worth of antibiotics. He said they usually do the treatment for six, but if she's not better in three weeks, we will have to talk about putting her down. The vet just kept saying how sorry he was.