Daughter doesn't list me as 'mum' in her phone anymore

I'm 79 and lost my second husband last year due to heart failure. I have two daughters who have helped me enormously clearing the garage and house of unwanted items, to the point where they have shown signs of stress and exhaustion. I've had two hospital stays for UTIs and delirium and I don't remember too much. They say I was nearly confirmed as 'lost capacity' and they had to beg the ward not to do the test. I am coping as best I can each day.
My eldest daughter and I have not really ever had a successful relationship. My first husband was violent towards her and either threw her about or shouted at her, first time she was 2 years old. I didn't feel I could do anything to get divorced as it wasn't something we did back then and I wouldn't have had any money but I eventually asked for a divorce when my daughter was 11. My daughter has been diagnosed with complex PTSD at the age of 43 and she can be very jumpy, grumpy or plain freaked out by things I say. She says I antagonise her and she has to go and calm down or cut the weekend short.
The last weekend she was down she showed me our texts between us on her 'phone to remind me of something she'd photographed and sent to me and I was saddened to see that she has me as a contact using my first name, not mum. I don't know why this upset me and I don't feel I can say anything, but I am just sad that she doesn't have me in her phone list as mum.
I feel very guilty about how I let things go on with her father and the damage is done. I'm scared of how my daughter is and how angry she must be. Sher manages to hide it most of the time but if she gets tired, it comes out and she'll snap. She does a hundred jobs for me and does them so efficiently but I never know how to speak with her. My younger daughter has mentioned that I don't ever thank my eldest daughter enough or show any curiosity about her life. She would have been an excellent wife and mother but neither of these things have happened for her and I don't think she's the marrying sort. She's had a string of unsuccessful or abusive relationships with men I'd have passed by.
I've asked my daughter to have a few weeks off from visiting me as it's now holiday season and she has a lady from Ukraine coming to her house to stay.