I shall never doubt myself.

Doubt has two jobs and only one of them is useful.

The useful kind checks the work — a surgeon confirming which knee, a pilot running the list she has run four thousand times. That version is precision, and you want it on your side.

The other kind examines nothing. It runs a general verdict about you, on a loop, usually late at night, usually with no new evidence since 2016.

Telling them apart does more than trying to eliminate both. Ask what the doubt is checking. If the answer is nothing in particular, it isn't information. It's weather passing through.