"'I will turn your religious festivals into mourning and all your singing into weeping. I will make all of you wear sackcloth and shave your heads. I will make that time like mourning for an only son and the end of it like a bitter day.'" NIV translation
Without their religious festivals, the people had no hope much like the loss of an only son in a family. The bitter day refers to the fact that they were going to be taken into exile.
"'The days are coming,' declares the Sovereign Lord, 'when I will send a famine through the land - not a famine of food or a thirst for water, but a famine of hearing the words of the Lord. People will stagger from sea to sea and wander from north to east, searching for the word of the Lord, but they will not find it.'" NIV translation
This passage speaks of the four hundred year period between the Old and New Testament. During that time, there were no more prophets sent to Israel. Going from north to east is a symbol of going away from the presence of God.
"'In that day the lovely young women and strong young men will faint because of thirst. Those who swear by the sin of Samaria - who say, "As surely as your God lives, Dan," or "As surely as the god of Beersheba lives" - they will fall, never to rise again.'" NIV translation
During that time of silence, those who trusted in the false gods would perish. This is much the same as what happened with Israel in the wilderness when they disobeyed God and would not seize the promised land.