So sorry for everyone's loss here. It's unfortunate part of life.
I guess the only thing I can offer is it will get less awful with the passing of time.
You are reeling now; don't make any major life decisions for a while if you can help it. I know for me, I was in a bit of a fog for a good six mos...things like losing my keys, forgetting stuff, etc. would happen. Your brain as well as your heart is still trying to process all this.
Realize it's perfectly normal to walk through a store and think, "Oh, Dad would love that!" As you reach for the item, you realize he's not here for you to buy it for him. Kinda jolting, but when that happens, smile a little smile and picture him in a pleasant moment, remembering something special or dear about him.
Eventually, the happy memories will outweigh the grief, and that is I'm sure how your Dad would want it.