Oh Hilda, it is so damn hard.
We want to do the decent thing for them, we owe it to them.
You say she is eating, drinking and " reacting " (bless her!) to the postman.
Apart from the bleeding and clots, does she seem in any pain or distress?
If not, then I would be inclined to just carry on taking each day as it comes.
One of my cats was very elderly, got a bit frail, but was eating, going out etc, then just quietly died. Another one was much younger, but having distressing fits, so we had to have her put to sleep.
Of course only you can gauge how you think she is feeling, but sending much love to you all. X