I feel helpless

Every single day I decide to stop masturbating. I pray and ask for forgiveness and ask for God's help. But then I keep doing it! I find myself watching R rated movies, or fantacising, or lusting at work. I have bipolar disorder... so sometimes I'm depressed or impulsive just because my brain is a little out of balance... I wonder if that is making things more difficult. No excuses though! Sin is sin. I'm trying to stay close to God... reading the Bible, praying, and worshiping God everyday... but I keep falling into masturbation anyway. Pray for me. I feel like a hypocrit every day when I decide not to fall again.