I was recently speaking to my friend over the phone. She asked about the whereabouts of my other friend, to which I replied "I don't know. I went home already." (Keep in mind that while saying this, I was already at home. After hearing this, my mother proceeded to comment on my incorrect grammar in the above dialogue. I was just wondering if 'I came back home' should be used instead of 'I went back home', and if the latter is grammatically incorrect in my situation. Thank you for answering.