I watched this yesterday too, but i cant say I found it very sad. and I dont know what you meant by her living with her guilt? Im now wondering if i fell asleep during the film!
Like others have said I did find the story line rather slow.
If it had been written by anyone other than Alan Bennet it would not have been worth watching. I watched it despite thinking I would be bored half way through, I wasn't, it was a joy to watch