Hemorrhagic gastroenteritis

My family has had dogs for 25 years. We’ve always had dogs. Holly, was 8yrs old, big girl about 70 lbs. so strong and healthy. Prettiest girl ever. Her only flaw was that she was, what we joked, to be a serial killer. She loved hunting and catching birds, whistlepigs, and anything that could be prey. We always were so proactive about getting anything away from her before she got hurt.

On friday morning holly started having issues and by 12:30pm she was gone. She had only shown signs of this for less than 6 hours. We thought we could make it to the hospital for her. She had hemorrhagic gastroenteritis, and it was a lot worse than we thought. We had dealt with this sickness in two other dogs who one was so much smaller than her and one was a lot bigger. Both were treated at home and then checked out when they improved. Why was this time so bad?? She was so healthy. I feel so guilty that she was suffering and we didnt know. We always checked all the dogs excrement and we gave them the best food for them, vitamins and supplements. Always had clean water. So much love and play time. I am so scared we robbed her of a chance. I dont understand how fast it was. It was a nightmare. Im so beside myself. She wasnt supposed to go.