Yes, I can understand why you're bitter; even Job in the Bible felt bitter when he thought God had abandoned him in his suffering. You can probably sympathize with his cry: "As surely as God lives, who has denied me justice, the Almighty, who has made me taste bitterness of soul" (Job 27:2).
But Job was wrong (as he came to see later on)! God had not dealt unjustly with him, nor had God abandoned him. Nor has God dealt unjustly with you or abandoned you. To be frank, you shouldn't be bitter at God. After all, God didn't put you in prison; you put yourself there because of what you did, and you alone are to blame for what you did. Sin has consequences, and we have no right to expect God to rescue us when we do wrong.
I realize this may not be what you wanted to hear–but I hope you can leave your bitterness behind. Bitterness is like a poison that will destroy you if you aren't careful. Most of all, bitterness will cut you off from God. The Bible tells us to "get rid of all bitterness, rage and anger" (Ephesians 4:31).
God loves you and wants to come into your life. He wants to forgive you and heal your hurts, and He wants to give you hope for the future. Don't cut yourself off from God, but by faith ask Christ to come into your heart. He will replace your bitterness with His peace and joy–and that is what you need.