Hi Flower,
I am so sorry for your loss, and know exactly where you are coming from as I went through the same thing when my Mum (who had Alzheimer's) died in June 2014. I think the death of a loved one who has dementia is doubly difficult because we grieve for who the person was before the illness, but also for the person with the illness who may have changed, but who we still loved so much.
Like you, I spent the last fortnight of my Mum's life by her bedside, wishing her in a way to be free of all the indignities of this awful disease, but still dreading the moment of losing her. Like you, too, I had a horribly unsympathetic boss. I will never forget the email he sent as I sat by Mum's bedside in the hospital two days before she died - he was asking me about where some documents were in my office, and if I could fill in some forms for him. He ended by saying "I know this is probably not a very good time to ask you this, but I'm sure you will agree that the good work of X committee has to go on". Just because Mum had dementia, he seemed to think that her death was somehow less valid, less important. It made my blood boil. Strangely enough his own father is now in a care home, and is suffering from memory problems, so perhaps one day he will understand.
I still miss Mum and think about her every day, but one thing I have found to help a lot is to have done some practical everyday things to remember her. Our local council offers various ways to celebrate a loved one's life, and I have had a laburnum tree planted in our local park, some daffodils planted on the ancient walls of our city and also sponsored a bench with a plaque in Mum's memory. Maybe you could do something similar? When I feel sad, or wish I could talk to Mum, I go and sit on her bench and look at her new little tree, now growing strongly, and it gives me a sense of connection and hope, just knowing that she is remembered. Although I am not religious, somehow I still feel her spirit and love in that place and it gives me peace.
You did everything you could for your Mum, and were with her to the end - that is the very best we can do for anyone we love. Those of us who have walked the same tough path are with you, and although we don't have any simple answers, we know that you will get through this, and that your Mum would be so proud of you.
Sending you a hug,
Margaret x