There will be moments in the life of a Christian when he will feel a great anguish and hurt and pain. There will be times when you will cry out the words of Psalms and feel as though you are suffering worse than Job.
But if you are constantly filled with bitterness against God, it means you do not know God. It means you do not know what gospel means. You do not know what grace means. You have not seen what has happened on that wretched cross. You have not tasted and seen that the LORD is good.
May you humble yourself before the Righteous God and may He fill your heart with His grace.