Somewhere in a long job search, most people start genuinely wondering if they're cut out for this at all. This is close to universal — including among people who go on to have long, successful careers — and it is worth naming directly rather than pretending it doesn't happen.
A job search concentrates rejection into a short period in a way daily life normally doesn't. A few weeks of repeated rejection, compressed together, would shake almost anyone's confidence — this is closer to a structural feature of what a job search actually is than a personal weakness in the person going through it.
A predictable feeling, not new information
The specific, common thought worth naming directly: "maybe I chose the wrong field." That thought is a completely normal response to concentrated rejection, and it is worth treating as exactly that — a predictable emotional response to a hard stretch — rather than as new, previously hidden information about your actual aptitude suddenly revealing itself.
Constantly comparing yourself to others' visible success, applying while genuinely exhausted rather than actually resting, and treating every single rejection as fresh, un-processed evidence rather than an expected, ordinary part of the process all reliably make self-doubt worse rather than better.
Ordinary discouragement during a hard search is expected and, in time, passes. Persistent low mood, real difficulty functioning day to day, or a loss of interest in things well beyond the job search itself are a different, more serious matter, and deserve real support beyond a career course — from someone qualified to help with that specifically, not from career advice.
Confidence in this field is built, gradually, by doing the work and seeing it hold up in front of other people — not by feeling ready first and only then starting. Most people who eventually feel confident got there by continuing to show up while still uncertain, not by waiting for the uncertainty to fully disappear before they began.