We all have this innate fear as to what will happen to us in the grave, but even there Allah Swt has promised a way for us, its a means of protection from the punishments and trials of the grave.
It comes in the hadith in Tirmidhi that Rasulullah Sallallahu alaihi wasallam has said that reading Surah Mulk before going to sleep at night gives one protection in the grave. It will intercede for the person who reads it.
Let us make a habit of continually reading the surah at night every night. May Allah Swt give us the strength.
May Allah Swt forgive us all and if you can, please remember me in your duas.