You are focusing hard and trying to banish the thoughts, and they are not going away. This is the nature of the mind, but it looks like you are very prejudiced against your mind. When you are doing your kriya or your meditation, you don’t mind if your kidneys or your lungs are functioning or if your heart is beating. You don’t mind all the other processes in the body – only your brain should not function! The notion that if you do something spiritual, your brain should stop working is simply wrong.