It's definitely true that the Ditto did not have an awesome human life, and rest assured, he will think about what he's lost. The main one is that the two characters were dating before, and they were together when "it" happened, and thus were both affected. But they didn't wake up in the same place. They start off separated. So the one problem that the Ditto has is that he misses his girlfriend. The Zorua misses her stuff, frankly. Which I guess says a lot about them. But the Ditto had always been inspired by Pokemon in various ways, but never had the starting funds to leave his livelihood to be a trainer or professor's assistant (or even a ranger, since he's from Fiore). The girl is the daughter of a successful pokemon breeder, so while she knows alot about them... she knows a lot about them. The ditto doesnt quite realize the implications of what he's become, which is partly why he isnt so worried. The girl is much more aware of these issues, which is why, at least subconsciously, she is much more upset about it. Ultimately, though, she'd be much more equipped to survive as a Pokemon than her counterpart.
Chronologically, it wouldnt make sense for us to learn about why he isnt so upset until he starts to think about things that he's lost, for instance. At least to me, anyway.
And yes, you sound kind of testy, but I wasnt worried about it.