"never mind i am" is not an expression by itself. do you mean never mind, I am going to go anyway, or never mind, I like it. The expression never mind probably translates as something like "do not worry" in spanish. Maybe "no te preocupes".

It depends. You need to tell us more about where you heard it. Litterally, "No te preocupes, yo soy." Or, "Olvidado, yo soy." Or, "No importa, yo soy lo que soy." It depends. There's just not enough information.

It is hard to know exactly what is meant without more details, but basically it is like saying "No te preocupas, yo soy" but "yo soy" could mean something like "ya estoy haciendolo" o "ya lo tengo". It depends on the context.