Cruel vs cruel

You see, I have a very old cat who has cancer in her nose and it is digging into her sweet little face. She has been so timid and fearful of people since day 1. The two times I have handled her much were when I got her neutered, and when the neighbor dogs played volleyball with her and I grabbed her to take her to the vet. I have fed her twice a day for about 19 years and she still acts like I'm going to kill her. So...do I grab her, shove her in a carrier, take her in a car, have other people handle her, give her a shot, etc., and put her down? OR, do I let her continue to lose weight (although she is still hungry and following her old companion around), get weak, and die in her own time in familiar surroundings? Both seem bad to me but it breaks my heart to think about terrorizing her for the last hour of her life. I want her to just go off and die on her own but I don't want her to die! I have such mixed feelings when I think she's not going to show up to eat, and then I have other mixed feelings when she does show up. My husband thinks I don't have the courage to take her to the vet. That's not the point. It's the idea of terrorizing her for the rest of her life that bothers me. What is wrong with me!!!