what next?

Lucy has had blood work done. Nothing definitive found other than some elevated liver readings. Dr. referred us to a more advanced vet clinic/hospital. xrays and ultra sounds were done on her. Still no definitive reason for her lack of appetite but we're down $1000! btw-her liver looked fine on the ultrasounds.
She's on prednisone, steroid, to increase her appetite. And another pill to decrease nausea. We're to try feeding her 6-8 times a day. The prednisone has worked. The first night she even appeared to be acting herself. Running around, asking for lovings, hungry. We went to bed hoping the medicine worked and cursing the money we paid for lab work. But the next day, she was back to not eating and not acting herself. And she had peed on her bad and ours, a lovely side effect of the steroid. We feel it happened while she was sleeping b/c no dog would willingly pee on their bed. We added boiled chicken into her bowl and she's been enjoying it. Sadly, there were still times she left food in her bowl. Today I've gotten her to eat 2 cans. She's suppose to have 4 a day, so I'm feeling hopeful.
I guess our next plan of attack is to continue this way till we run out of the meds and see how she acts then. The anti-nausea medicine runs out tonight. steroid, wednesday.
Decisions like this are so difficult. We know that Lucy isn't suppose to have a long life. She just entered senior stage at 6 years old. But I was so upset Friday. I looked at Trevor and said if it's her time I sure don't want her to die due to starvation. That seems cruel. But with nothing showing up on all those tests it seems unlikely any further testing is going to produce anything. I guess if she begins to decline after the meds are gone, we'll look into keeping her on them.