Im afraid guilt appears to be a normal step in bereavement. I certainly had plenty of 'should haves' and 'what ifs'. I'm mostly at peace with them now. It can take time for us to understand/believe deep down that we are not to blame, but we aren't to blame, we are all human and we all do the best we can at the time with the information available to us at the time. No-one can predict the future with certainty
Even though you had a feeling it may happen, it wasnt for certain. I don't think you should blame yourself atall, I think things happen as they should in a way.
Be gentle with yourself, I think its a normal part of loss xx