Is “am” ever proper English without an “I” somewhere before or after it? [duplicate]

For a long time, I have been convinced that the use of the word am without the word I either before or after it is incorrect. For instance, saying Am going all by itself.

However, I recently ran a search on it to try and clear up the confusion, but that has left me even more confused than I was to begin with!

The pronoun is sometimes omitted in a text in note form. It is required otherwise, and it is usually present in speech.

People will understand what you mean, but the only context in which you'll see it is a hastily written note or text message. In spoken English people would say "I'm ...". In some dialects this may sound like "Ahm", but it still means "I'm". It would definitely look like an error in a formal context.

You might encounter it spoken in a police or similar radio context, which has its own dialect and idiom: "Roger control, am proceeding to location bravo".

One case where we accept "am" with no pronoun is the childish rejoinder "Am not!" or "Am too!". For example, "You're stupid!" "Am not!" or "You're not going with us." "Am to!"

This might also happen in an informal note to someone. "Am going shopping. Back soon." I don't think I've ever heard anyone say this out loud, though.