get down vs. get depressed

English Language Tests, Intermediate level

ESL/EFL Test #75 [color=blue]“Christmas Postman (2)”, question 8

Ted was always calm and optimistic. He never let himself get by the job.

(a) doomed
(b) downgraded
© depressed
(d) downed

English Language Tests, Intermediate level

ESL/EFL Test #75 [color=blue]“Christmas Postman (2)”, answer 8

Ted was always calm and optimistic. He never let himself get depressed by the job.

Correct answer: © depressed
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Hi,
I know the correct answer is" depressed", but I wonder whether it is correct if I say “ he never let himself to be got down by the job."

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It sounds possible but extremely awkward in the passive. (And no ‘to’.)
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