I know what you're going through mate, my dad died coming up for four years ago and me and my mum were dreading all the "firsts" as well as the anniversary of the day of his death. These things will be different for everyone but on the actual day of whichever "first" it was then this gif probably sums it up best for me and my mum-
For all the dreading of it, it was a day the same as all the others, just another day when he wasn't around, no more or less difficult than any of the other days. It does get better over time, not so much getting over it as learning to live with it. You'll get there, you're more than welcome to PM if you want to sound off.