I think you might be surprised at how many people in these situations have pretty much exactly the reaction you have had. It doesn't mean you loved her any less. It's not a contest.

My mother died in 2004 of a bad lung cancer. It had been a long illness and she was really suffering and, tbh, I was relieved when she died. Not for me, for her. She literally could not stop coughing. So, there weren't a lot of tears for me. But, of course, I loved her. She was my mom.