Fear of Loss of Self in Work

One of my recurring fears relating to work is being afraid that jobs will cause me to lose my self. Let me try to explain.

What this looks like for me: When I spend a fair amount of effort in any kind of repetitive work-like tasks, such as data entry, accounting, database searches, etc., I often feel that my own thoughts are vanquished, and somehow my self, or my me-ness, or identity, is lost.

I then feel like I don't exist during those periods.

I have a hard time returning to my own thoughts and sense of existence and identity after prolonged periods of external work, particularly if the tasks aren't intrinsically interesting to me. I go blank and feel mentally drained, sometimes physically drained also.

It can feel like losing my life a little at a time. Depression feels similarly to me. There's a sense of mental blankness and feeling less than fully alive. I feel like I am "not present."

I don't understand why this happens. Nor have I heard other people describe feeling this way about their jobs.

It's been happening to me again lately, now that I'm working. The more I work, the more I have these detached feelings of unreality. It's a very weird feeling and it's not one I feel I can fully describe or understand. Perhaps I will tell a therapist about this, or try to research what the hell this is.