Nervous about submitting a paper - what if I made a mistake?
(Upon @Massimo Ortolano's kind suggestion:)

Your issue is not even about "retractions", much less "breach of ethics", if you (and all your co-authors, and advisors/mentors) are acting in good faith. "Making a mistake even with due diligence" cannot be a punishable offense, or no one at all risk-averse would ever do any new work/research/etc. In other words, it's not like a school course where there is some "ultimate judgement" and "absolute standards". In this regard, many school systems from kindergarten through high school (the U.S. name) through undergrad school (the U.S. name) cultivate terrible reflexes, yes.

That is, even if you did make some sort of serious mistake, it's not like it "goes on your permanent record, and a letter is sent home to your parents, and you'll be 'grounded' for two months". The paper just gets rejected (if the referee detects your supposed error!), and hardly anyone in the world knows about your gaffe... whether or not it is upsetting to you personally. People have to "go out on a limb" (English idiom) to make serious progress, and this oughtn't be punished.