Perhaps the feelings that you said were guilt aren't really guilt, but a strong desire to have had things go differently? This could be especially with regard to what you did or didn't do, and how you responded emotionally. Perhaps you wish you had felt differently and done more. I wouldn't associate those things with guilt. (As I said, guilt means you did something wrong.)

We all wish for things to go as best as possible, to have and help others live well and long... I hope you can gradually reframe those feelings, pulling them from the "guilt" category and placing them someplace more palatable.