What you mean by "miss" and what she means might have different connotations ("denote" is literal meaning, "connote" is a "commonly understood subjective cultural and/or emotional association"). I would say that thinking about someone else, for whatever reason (if you sent her an email she read, for example, whether or not she was on vacation; you and she are not "together" then) would be a form of "missing" the other person, otherwise you wouldn't have thought of them? When I do something and it reminds me of a friend, what T has said to me, or anyone else for any reason (even my dead parents), I wish I could tell them about it right then, could show the person? So, I'm "missing" that person.

No, it doesn't have the nature of our constant-seeming thinking about T at every turn, but I think she did think about you for some reason and missed you, that's why she told you! She wanted you to know she had thought about you and "missing" is one way to help ourselves connect with others. You go back to T because you miss her :-) She sees you because she enjoys seeing you and misses not seeing you!