It took him 3 days to get right with God and decide to go to his enemies and preach to them.
When we disobey God, we are cut off from blessing, from our mission, from others, from the light of day. Just as Jonah tried to run away from his purpose, he was alienated from people, and literally got eaten up by the situation.
It could have been the end for Jonah but we know it's just the beginning. He realizes he can't run away from his destiny and his God.
He prays and at that moment, he is conveniently catapulted into land - and he then knows he must do what he must do.
Sometimes we find ourselves in darkness and though we are paralyzed by fear of what's to come, we somehow know what we need to do (but somehow don't want to do). Just like Jonah, we can pray, and be empowered.
Until we do what we were created for, we will be in this deep, dark hole of nothingness and our future can be as bleak as someone who is in a whale's belly. All we need to do, to find the strength to "just do it" is to pray and put one foot in front of the other knowing that "all things are possible for him who believes". (Mark 9:23)
If Nineveh can be forgiven, then so can I.
Nineveh was a place just like Sodom. It was a very ungodly place.
But the story of Jonah is a prefigurement of Christ's coming.
Like Jonah, Christ was in the dark depths 3 days, and afterwards, His saving grace allowed us to repent and come back to God.
Jonah had to save those who oppressed him just as Christ did, and just as you and I are called to do.
We are surrounded by people, and people can unwittingly hurt us. Let's love and serve others even when they've been a source of pain for us. This is one of the secrets of this story.