Ok you can read this du'aa "Allahumma innee a3uuudhu bika min 3adhaabi jahannam wa min 3adhaabil gabri wa min fitnatil ma7yaay wal mamaat wa min fitnati masee7u dajjaal"
O allah i seef refuge in you from the punishment of jahannam (1 of hells names) and from the trials of the grave, and from the trials whilst dead and alive, and from the trial of the antichrist (dajjaal)
hadeeth is sound its in bukhari and muslim,
I think its reported by abee urayra, but i will make sure of that inshaAllah,
wassalaam