the pit of your/the stomach
the pit of the stomach
An area in the core of one's abdomen, approximately in or near one's stomach, in which one feels a physical response to strong emotion, especially fear, stress, or anxiety. The film leaves you with an awful feeling of dread in the pit of the stomach as you realize that, not only could something like that happen in real life, it could happen at any given second.
pit of one's stomach
Fig. the middle of one's stomach; the location of a "visceral response." I got a strange feeling in the pit of my stomach when they told me the bad news.