My impression, and I do hope I'm right, is that it's less "Harry isn't happy at all" and more that things from his past come back to haunt him, and that there's already some things in his life that are out of step - which makes sense anyway; he's Head of the Auror Department and has three kids, and he'll still have the pressure of being the Boy Who Lived. I just hope, like you said, that it's not that he was never happy.

I liked the epilogue but had issues with the names. Of course, like you I was also thrilled with the pairings, so that also helped.