Need help identifying epistrophe

No, that is not an example of Epistrophe.

Epistrophe is rhetorical repetition that occurs across different sentences, phrases, or clauses. Your example is repetition for meter and emphasis, not for rhetoric. It doesn't occur in different sentences or clauses, but repeats the end of one sentence.

You are correct to observe that "you, you, you" does not represent three different clauses, because there are not three verbs.