Do the thing we fear, and death of fear is certain.

Fear survives on distance. As long as the thing stays ahead of you, imagination keeps supplying worst cases, and the dread grows in proportion to how long you leave it alone. Doing it collapses that space. Whatever the outcome, the version in your head stops being the only version you have, and the particular fear attached to it cannot survive contact with the actual size of the thing.

Choose the smallest real version of what you have been avoiding and do it in the next few days. Make the call, send the message, walk into the room. Afterward, notice how much of the dread was about the waiting.