you left her because you are not a fulltime carer but a person who has to live her own life; you just can't be with someone 24/7. No wonder you feel hard hit, you lost someone close to you, but it doesn't sound to me as if you did anything wrong at all; and if you had been there, really, would it have made such a difference?
I know it's tough, we're all going to be old some day and we hope people will be round us when we go... but you know, if I'd been her I don't think I'd be blaming you in any way.
No slating for you, no way.