Finding the thought creating the feeling

Good Morning,
I seem to be engulfed in a strong physical feeling this morning of heaviness in my chest, full body lethargy, and slight nausea. because the feeling is so all encompassing I am having a hard time finding the though that is creating it. I have a sales call this morning, and I believe it is a thought related to that. In not resisting or reacting to the feeling, how do I access the thought causing it? My sense is if I push it away I’ll find out whats causing it, but then I am not allowing it- Advice? Thank you !!!!!