At first I thought John had gotten depressed after Sherlock died, had killed himself and Sherlock had come back and had found John's grave (aren't I morbid?) John he cares about you, he really. Sherlock has a weird way of showing affection doesn't he?
Oh god. This is so sad but SO TRUE. Like, my romantic side wants to go "NO, HE'D CARE MORE THAN THAT, HE'D BE SO LOST." But the logical part of me is just like "shit, that's totally what Sherlock would do."