Don't get discouraged by it, see my post above. Your writing's fine (except for one thing 😡 ).
I recommend for the accusations that you run your writing through detection that does a macro and micro scan, alla Originality or GPTZero. You might get an occasional false positive for a few lines, but you can take that as a cue that that part of your writing sucks so bad it sounds literally robotic, and you can revise it. Or just leave it alone, up to you.
(On the off chance a machine is writing the whole thing and you're just revising/editing, using tools like these will make you spend so much time "revising to sound original" that you'll feel like a loser who should've just written an original text himself from the get-go)