I agree that counseling could be of great benefit. You could be in a bit of 'shock' from the death. I had this from my mother's untimely and tragic death. I had bursts of reality hitting that were so intensely painful that I reacted physically. I slept very little and did things like copy the entire New Testament of the bible into a note pad. Wrote into a journal every one of the recipes in my sisters vast cook book collection as well. It was all shock and intense grief playing out in me. Grief counseling is very helpful and helped me very much.
I also did go away but more in terms of changing things up. Instead of the typical family Thanksgiving, I went away to the beach. That first year is rough.
I'm very sorry for your loss dear. We do also have a grief forum you may find good support from as well. peace
If you didn't grieve you would not be human. Everyone tells you it becomes more bearable with time. And this is true but it doesn't make the present any easier.
I will make an unusual suggestion. Go away on a trip, a trip to somewhere you have never been, a place completely unfamiliar. The disruption may help, at least in the short term.
It might be a good idea to get grief counseling. You're probably doing better during the day because you're keeping you mind busy. At night you have time to think about what happened.
I'm so very sorry for your loss. We're always here to listen and help any way we can.