Hi Suki,
So sorry to hear your mum has passed away. In time you will take comfort in the fact that you were a loving, caring daughter to your mum, and could have done no more.
When my mum was "waiting for God" (her words, not mine) almost six years ago now we had a rota so she was never alone. The night she passed away I had gone to take a steak pie out of the oven for my OH and Dad for their dinner and shuddered as the heat from the oven mixed with an icy cold blast behind me. That was the moment mum chose to pass away, when no one was there. This has happened on numerous occasions during my years working in hospitals, so please do not feel bad that you were not with your mum at the very moment of her passing.
Take a day at a time and do only what you want to do, or feel you are able to cope with each day. Most of all, take time for yourself, and sound off on the forum whenever you want, if that helps. Finally, take comfort in the knowledge you are not alone, we are all here for you.
Take care
Meg