B'sidhe has died

B'sidhe has died. 
The past couple of days have worked out that I encountered an opportunity for overtime.
My hope was that I'd be able to pull together enough to pay for B'sidhe to go to the vet and that I'd be able to cover whatever procedure would be necessary. 
Unfortunately, the timing wasn't right. 
B'sidhe died. I was doing some cleaning and I found her in the bathroom cabinet. 
She was with me for 17 years...

B'sidhe

B'sidhe is dying. I know that deep in my heart I expected this one day...I just didn't expect it today.
She's the cat that came into my life the day I lost Pyewacket to some speeding douchebag.  
It's so hard to believe that happened over 17 years ago....just a couple of days ago, she was her usual self, climbing where she knew she wasn't supposed to, giving everyone (Polgara and Cleopatra) absolute hell, and doing her "I'm lonely, where's everyone" yodel.
Now, in just a couple of days, she's lost a serious amount of weight, she's lethargic, refusing treats, and the biggest shocker of all, she was going to allow Cleopatra to steal treats literally right from under her nose. One thing you never ever do is try to steal food from B'sidhe. She didn't hiss, she didn't swat at her, she was just going to allow it to happen. That's what's freaked me out the most.


I'm going to take her to the vet tomorrow, to determine what's wrong aside from old age.
Then I'll have to make a quality of life decision. I don't know what to do. 
If the Dr says she's in pain, do I spare her pain and have her put down then? 
Of course, best case scenario is that the vet will say that she's just old and a vitamin shot will do the trick.  
Unfortunately, finances are also a major part of this.
I simply cannot afford to pay out thousands of dollars for treatment that may or may not work. 
Hell, I can't even afford that for myself.
And the even bigger bitch is that her vet, Dr Gordon, retired years ago.  He was affordable and would have given me a straight answer to this issue, and would have worked with me financially.
Now, I'm looking at trying to make a vet understand that I appreciate honesty above all else, and that they'll be *very* sorry if they try to talk down to me.
Crap.  I'm digressing. I'm going to try and get her to eat something now.
I'll post more after I know more.

Observation

As you know, Andrea, I have 3 cats right now. B'sidhe, Polgara, and Cleopatra.
Well, in preparing for the roadtrip to see you, I had to figure out how to keep the cats fed and watered for about 4 days.
This shouldn't have been a problem, except that I needed to get what's known as a gravity feeder. Located one, and it held approximately 10 cups of food.
Which, properly rationed, is 10 days worth of food.
Please note, properly rationed.
I filled the thing before I left the house on Tuesday. I got home early Sunday morning, and found crumbs.
4 days. And honestly, I do believe I know who the culprit is. It's Cleopatra.
Her favorite position is a face plant on the food bowl.
Well, just wanted to rant.