Need advice on a decision I made

I am retired and living on SS only so I have recently been looking for a part time job. My anxiety has been at an all time high recently (as well as depression) and especially my health anxiety. However, someone turned me on to a job taking care of a woman age 75 with ALS and has no use of her arms and hands. She is a sweet little lady and has been through hell in the last year....diagnosed with ALS last September and in October lost her husband of 51 years to cancer. I started today (it's only from 9am to noon) but I left there feeling even more anxious and depressed than usual. She told me she wishes she could just die because there is nothing to look forward to except getting worse and becoming more of a burden on her family PLUS she wants to be with her husband in heaven. She is very alert mentally so it must make this all that much harder on her. Selfishly, however, (and that's how I feel, selfish) I'm worried that this may not be a healthy situation for me to be in right now since I'm suffering so much with anxiety and depression myself. That may sound heartless but I have a family to think about too. I was shaky and anxious all the way driving home and was even convinced I had the same cancer as her husband did after she told me his symptoms! I try very hard to be upbeat and positive when I'm with her but it obviously takes a toll on me, since I fell apart after I left. Do you think I should just stick with it for awhile or do you think it's the wrong type of job for me. The money is good and under the table so I hesitate to give it up so easily. I know the family would have to pay alot more to a professional and i hate to see them have to do that, but I get worried also if something should happen to her while I'm caring for her. She already told me she has swallowing difficulties and food sometimes goes down into her lungs instead of her stomach if she's not very careful. Only thing good about that is that she has no appetite at all and eats only soft boiled eggs, puddings and thickened drinks. Am I putting both her and I at risk?

Thank you so much for your wise advice. I think I will give it this week and see how things go and then make a decision. I would love to think I could do some good for her, and maybe take my mind off myself for once too, but at the same time don't want to jeopardize her condition or exacerbate my health anxiety and depression. She has deteriorated very quickly apparently....diagnosed just last September, then just lost the use of her arms and hands this past June. So I don't see anything good for her going forward, poor thing. It would also be difficult for me to watch this deterioration as I become closer to her. So there's alot to consider, not the least of which is the risk factor I mentioned if she should suddenly start choking or something. I will certainly let you know what my decision is but in the meantime thank you for your support and advice. This forum is my lifeline....much better than any psychiatrist could ever be.