In those days Hezekiah was sick and near death. And Isaiah the prophet, the son of Amoz, went to him and said to him, “Thus says the Lord: ‘Set your house in order, for you shall die, and not live.’ ” 2 Kings 20:1

There are things I would not mind knowing about the future but the day of my death is not one of them.
That’s exactly what Isaiah tells Hezekiah. He isn’t told when only that his present illness leads to death.

Several things happen that turns it all around.
First of all, Hezekiah prays, which is the right way to go.
After pouring his heart out to God, God gives him grace and mercy. God adds fifteen years to his life and spares Jerusalem from the Assyrian army.

Still unconvinced Hezekiah ask for a sign of assurance and receives it with time going backward by ten degrees on a sundial.

Perhaps you received some bad news lately. Maybe the doctor said the words fatal, terminal, little hope, or gave a timeline of weeks to live.
Do as Hezekiah did – pray!
I believe it’s alright to ask God for a sign. Perhaps in His mercy, He will grant it.
He gave signs to Moses, Gideon, and Hezekiah just to name a few.
Jesus gave you the greatest sign – the sign of the prophet Jonah. For as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth. Matt 12:39-40

Personally, I have asked God for a sign and He answered. I find it strengthening to my own faith.
I know others that did the same and found the same.