When doing this and a thought comes along that is judgemental, label it as "just a thought". Another thing to just notice, to watch it come and watch it go. You can write them down as a way of observing them and a way of letting them go. That helps me.
"Thoughts are just thoughts" is a powerful phrase taught to me by someone who was very helfpul.

For me it does help to just let it happen and not distract it. I have learned much about what's going on and where this feeling has come from by letting it happen. And like all moods, it has a beginning and an end.
It's good to remember there is an end, it will pass, it isn't going to stay forever.