I'm so sorry, I know how awful it is. There's no good way for them to go, really, our beloved darling died quickly, on our bed, surrounded by us, and it was still hell. I remember people saying about the pain easing and you'll remember her and smile and I thought 'no way will I ever feel better', but almost a year on I do.
They leave such a huge void, they make a house a home, and you won't know what to do with yourself. I'd say leave her stuff out for a wee while, once it's been put away, it's away IYSWIM. I cried every way possible, on the floor, on her pillow, in Tescos meat aisle, everywhere! You've lost a cherished family member, do whatever you need to do in your grief.
I lasted one month with no dog, then made a trip to a kill-pound and now have another darling, who helped massively.
You will feel a bit less shit in a week, then a bit more, then a bit more, I promise.