She is at peace now ((katydid)). Sometimes we just can't be there for our loved ones when they pass away. My MIL went into the hospital for surgery to see what a mass was inside her and try to open up a passageway that was blocking her ability to pass bile correctly from her stomach. I did not know how serious it was and thought it was a simple procedure. She made it through surgery and the next morning when they brought her breakfast she said she felt nauseous. The nurse when to get something to help her with that and when the nurse returned my MIL had passed away. I did not get to say goodbye to her or talk to her, wish I had and she was alone when she passed to. Unfortunately, a lot of people are alone when they pass away. My MIL's heart stopped and she did not know she was dying, it was quick. And actually, I had learned that they discovered she had pancreatic cancer and the tumor was bigger than they thought too so had she lived she would have suffered and been in a lot of pain. Sometimes, a death like that is merciful in that the person doesn't have to endure a long painful death.
I am sure she knows you would have been with her if you could.