Keep it up, man (no pun intended there!). Always take some time for yourself to do what you love (gaming, nature, trips, etc). and that depression will be curbed, trust me!
I'm sure the Japan trip helped perk you up a bit
Me, I just have kyphosis (hereditary, sadly), but my lower back (the spine area) is always in a state of perpetual pain; I have a super, SUPER high pain tolerance, so I've learned to deal with it, but its just always there.
I too sit at a desk all day and that's why I've gone through some weight gain, over the past few years (and my schedule sadly, doesn't allow me to spend a lot of time at a gym and I need to cut costs too). I am walking to work and back (combined 10+ km each day), which is helping (already down 5 pounds in 2 weeks), as I've always eaten very healthy.
My worry is that, like you said, I will start to not be able to do things I used to do; I've had this back pain (and a torn muscle in my back that didn't heal properly, when I was 18), since I was a teenager and eventually, it HAS to start affecting my abilities, right?
Just hoping that also, like you said, I progress and get better into my thirties, as that's possible too, right? lol