Hi Kim, im so sorry for your loss.I was with my mum when she passed away from lung cancer,it was so traumatic i know exactly how you feel, for months and months i kept reliving the last minutes wondering if i could have done,or said something better, i know i did my best as you have done for your dad, its an awful trauma you have been through that will take as long as you need to start to recover, look after yourself and be kind to yourself, you were with him when he died so he wasnt alone,its a wonderful thing to have done for him.