This is Your Anxious Brain on Meditation

In mindfulness meditation, when you notice a thought, you’ll likely be tempted to dwell on it and take it somewhere. Instead, you can just touch it lightly with your attention and go right to your breath. It doesn’t matter if you were off in space for a long time. In the moment you touch the thought, you can bounce right back.

Source: This is Your Anxious Brain on Meditation – Mindful

This talk from Tara Brach may help with this issue!