Such sad news Tez, very sorry to hear of your Dad's passing, 57 is far too young, especially for someone who looked after themselves like it sounds like he did. Be very thankful your dad got to see you get married and saw your kids.....my mum passed away just over 3 years ago from cancer and she wasn't here to see me get married or meet my kids, it is the one thing in life I wish I could change (other than her still being here).
I'm glad you made this post, the best thing you can do is talk about it with people. I've found time to be a very slow healer but talking about your feelings with people close to you is the best thing you can do.