Granted. The limits of your human mind remain the same: too small, too fragile. Unable to comprehend the breadth of the cosmos itself, you're now like a rubber balloon trying to contain the ocean. You go immediately insane.
Granted. You now hear the voices of all humanity crying out at all times. The noise is absolutely unbearable! The weight of the world's anguish now reverberates inside your head. You wish for death, but you are now immortal.
Granted, you become omnipotent. Unfortunately you cannot control how much power you put out and break everything and kill lots of people and eventually yourself.
The universe is infinite, and trying to find Earth is like trying to find a molecule in the ocean. You could control what happens there if only you can find it.
Granted. As a mortal brain changes to immortal, there is no start, so you get confused about when anything happens . the confusion persists until you devolve into seeking a hit of any drug (alcohol mostly). You take up holding a hammer