There is absolutely nothing wrong with the sentence in certain circumstances and with certain punctuation features. If, for example, the speaker is reporting a conversation he had earlier with someone else, he might just have said of that other person, "He said i was always repeating myself." To indicate what response he gave, there is no earthly reason why he should not say, "I said, 'I never repeat things.'" In other words, this is a piece of reported speech. In print, the extra single inverted commas are used, but, of course, in speech - unless we're Victor Borge! - we don't insert punctuation marks, do we? In other words, if the sentence in the question is spoken, it sounds fine.