Feeling of guilt after hospice medications

I've been feeling like after being a caregiver my whole career and then spending a decade caregiving my Mom, medicating her during her last days for comfort purposes I keep cycling back to the knowledge that it she might have rebounded again and still be here with me. It's the kind of Schrodinger's Cat scenario and part of me feels relieved that she's at peace but also feeling like if I had done things differently would she still be alive and well. After loosing my Dad when I was 14 I only want to save lives and having a distinct feeling of guilt that I could have been the reason my Mom is gone now too.