Short spoken explanation about why people experience a "sinking" feeling: negative thoughts (or thoughts attached to situations) create meaning which produces feelings like fear or discomfort. The speaker advises recognizing these thoughts as the source, disputing their truth, and deliberately changing how one responds so the feelings stop dominating.
Do you get a sinking feeling as if something's wrong? It comes from a thought or a situation that your brain latches on to, or a thought that's attached to that situation that says something bad is going to happen, or there's something wrong. It's just your brain taking a negative thought or situation and giving it meaning. And then our feelings develop from those thoughts. And so once you learn what's going on and you can determine what the fear or the discomfort is, then you can rewire your perception based on that thought. So if that sinking feeling has plagued you before, I want you to remember that this is just a feeling coming from thoughts, and it doesn't mean that those thoughts are true. When you learn what to do with uncomfortable thoughts and feelings differently than what you're doing now, you can turn it around so that they don't bother you.
