While praying to Lord Krishna, sometimes my mind says He is false. What should I do?

From: Birendra

  While praying to Lord Krishna, sometimes my mind says He is false, He is not God, He is a thief…so on, whereas my heart says he is God. Why do my mind and my heart differ? Although I feel guilty for entertaining any negative thoughts, they are they because the more I try not to think about them they are there because not to think about them make me think about them.