Why does my anxiety spike when I try to be non-judgmental about my thoughts?

The core of mindfulness is non-judgment, but the moment I try to let my negative thoughts pass, my inner critic attacks me for being lazy or passive. This internal conflict causes an immediate spike in anxiety. How do I train my brain to accept the thoughts without engaging in the judgment? My name is Neha. My DOB is 29th March 1990, born at 10:00 AM, in Lucknow.