Grisou's tail curled over his back

Grisou is about three years old. This January he was bitten in his front leg by his big bro' (The Rogue), with followed successful re-introduction and recovery indoors for 3 weeks. For the last two weeks, he is happily using the cat door again, friends with The Rogue, extremely confident thanks to a little antidepressant pill (Sertraline = Zoloft, which also stopped the Rogue spraying and attacking everyone). Only now he is carrying his tail curved over his back like a pug. There is nothing wrong with the tail that I can figure out - but he has never, ever in his three years before done that. I was looking for side-effects like appetite loss, which he definitely hasn't - he gained some weight instead due to not having to look over his shoulder while eating the whole time. Should I be worried? 

Can we see a picture?

coming up tonight - sorry I posted without one. Have to get him walking, he doesn't have the tail noticeably curled while laying or sitting...

now with pictures (he didn't quite get what the fuss was all about, kept wanting to lie down and purr

as you can see, the tail curls not when he's laying down, only slightly when sitting up, but totally pug-or pig-like when walking. Normal or sudden-onset of something I'm worried about?

That's quite something. Maybe he's just a very confident cat. My cat's tail is very erect when he is walking, and if I try to push it down, he cries out in pain. It's also very, very hard to push down. The tail is an indicator of the cat's mood.

I don't think there's anything to worry about. Evidently, the Zoloft has given him a super dose of confidence. 

Thanks much for the reassurance!

Is anyone else out there with cats on Zoloft (Sertraline)?