It sucks my brother, just no other way to put it, it just plain sucks. You are not alone in your thoughts/feelings/emotions. Lost my Dad at age 60 in 2003, about 3 weeks after my daughter was born. He never got to see her. It still saddens me to this day on what all she could have learned and enjoyed from grandpa. One thing I've come to realize, and as I'm 53 myself and getting older, is that death is a natural process that EVERYBODY goes through/grieves. You have to handle it your own way. But, I keep his memory in mind akin to WWJD thing...but it's more like What Would Dad Do? Keeps me sane and in-check with myself. He wasn't perfect....hard drinker and chain smoker, but I've learned from that so that those mistakes are not carried on witnessed by my daughter. That's not to say you can't do some crazy things, but just keep that line boundary within yourself. I drink, but I don't get crazy and just enjoy some wine/beer at the house on weekends in the evening. In a way, I'm passing my knowledge gained from my father to her but straightening the wrong things he did along the way to right the ship. You'll never forget them. Never. Don't try and fool yourself thinking you will, because you won't. You can't drink them off your mine, as most country songs go. BUT, that's a GOOD THING!!! As a parent myself, getting close to the age my father passed, I have often question myself if I'm teaching her, showing her or setting enough examples whereas when I pass, will I feel good about what all I've done as a parent? To that, I say, finally, YES. I now see it in her...her compassion, love and spirituality she has within her. I like to think I've guided some of that. From what all you've said before, it appears to me that your mother has done the same. You carry yourself upright and in the eyes of your mother.
Things will get better. Not overnight. It's a process. Focus on the good things and cherish the memories. Be grateful as #ell of those wonderful memories. One thing I did when my daughter was born was start a diary for her. I'm now up to 5 composition notebooks. When Dad passed, I wrote about 10 pages telling her who her grandfather was. What he did, places we went, the things we did, both good and bad. I hope one day she reads it and gets a mental picture of him. I keep a couple of pictures of him in the house as well. Now, 14 years later.....I still miss him, BUT, it's with a smile. Remembering him and laughing at all the crazy kraph he/we did. From since I was newborn to about age 12, he was a single Dad with me and we were in Germany for 6 of those years during the late 60's and early 70's, boy, did we go places and see things. Hang in there, it will get better, I promise. I'm an living example.