How can I better understand the difference between warnings from the Spirit and excessive worry?

The Holy Ghost is the Spirit of Truth and the Spirit of Peace. The Spirit typically works quietly (see 1 Nephi 17:45). Thoughts caused by anxiety are loud and intrusive, making it difficult to feel the Spirit and to depend on your faith. Faith is trust in God. The opposite of faith is uncertainty and mistrust, and so anxiety disorders often undermine faith.

The Book of Mormon prophet Jacob explained: “The Spirit speaketh the truth and lieth not. Wherefore, it speaketh of things as they really are, and of things as they really will be” (Jacob 4:13). As you learn to listen to the Spirit, you will be better able to discern between truth and the discouraging, untrue thoughts caused by anxiety.

Faith in the Savior’s Atonement and Resurrection, combined with hope and charity, should anchor our lives (see Moroni 7:40–48).

See also “Anxiety and Anxiety Disorders,” Ensign, Mar. 2017, 54–61.