I'm so sorry for your loss. My eyes fill with tears reading your post, because I know it's only a matter of months before it's me posting about my dad.
Be gentle with yourself. There's a time to grieve, and you have to give yourself permission to let it out. There's no path out of grief except right through the middle of it.
I'm so sorry. I hope you have many good memories to comfort you when the worst of these feelings have passed.