We usually say 'Me too' rather than 'Me also'. There's nothing wrong with 'Me also' - it's just not as common as 'Me too'. However, neither of those responses work in the 'I love you' conversation. The exchange should go like this: 'I love you' 'I love you, too.' 'Me too' would be a strange thing to say in this situation. It would mean 'Yeah, I'm great, aren't I? I love me too!'