Can't sleep after my father passed away

He was in his 50's, biopsy came exactly a month before he was gone, stage IV, he used to call me everytime he needed something. His last week was so unbearable to watch, yet he went away so silently without any signs of pain or death. There were so many complications, had to get PTBD for drain after the first chemo. Spent a night in the ICU, as soon as he got better, he said I'm good, I'm getting better, I want some food, next moment he was gone holding my hand with no struggle, no pain, almost like he went to sleep. It was hard, unbearable, Still can't comprehend what just happened.

Everytime I close my eyes I hear him calling me, I don't know what to do anymore, I've taken sleeping pills, anxiety meds, stress relievers, EVERYTHING. I haven't slept for almost a week now, I need advice from those who might have gone through something similar. Please help.