Welcome to the forums! I'm sorry you didn't get your post answered in over a week.
I can't speak on the specifics of neurotransmitters and the chemicals in thereof, but I can at least give my experience and ask a few questions about yours. I haven't traveled across the world but I've taken a few flights to different states before. The furthest that I've traveled was Texas. Arriving there was fine; I actually spent a great deal feeling happy about myself for once. Leaving was different, though. Returning to my murky hometown was a surreal experience and it took me a moment to reconnect with everything around me. My brain was stuck in Texas, I guess.
I'm also a sufferer of seasonal-affective disorder and I think that my brain's unwillingness to leave Texas when I returned had something to do with the months that I traveled. I left in at the beginning of August, which is usually when the feelings from SAD start to affect me. Arriving in Texas, it was quite hot and sunny. Maybe my brain was processing the season a bit differently. It felt like it was spring there. Upon returning, I think there was that initial shock of it actually being winter where I lived. That actually caused whatever mechanisms in my brain to mix up seasonal-affective disorder to the point where I actually suffered for longer that year.
Perhaps that's the center point of your issue? Maybe the combination of your circadian rhythm getting mucked up - alongside the seasonal-affective disorder - has your brain trying to calibrate itself constantly without success? When you mention that you felt this way before in 2017, did you do anything specific to alleviate the symptoms or did they just dissipate on their own? Sorry I can't be of more use! Although, you seem to have a pretty firm grasp on your own psychology better than most, so here's to hoping that you've gotten a bit better since you posted this.
I can't speak on the specifics of neurotransmitters and the chemicals in thereof, but I can at least give my experience and ask a few questions about yours. I haven't traveled across the world but I've taken a few flights to different states before. The furthest that I've traveled was Texas. Arriving there was fine; I actually spent a great deal feeling happy about myself for once. Leaving was different, though. Returning to my murky hometown was a surreal experience and it took me a moment to reconnect with everything around me. My brain was stuck in Texas, I guess.
I'm also a sufferer of seasonal-affective disorder and I think that my brain's unwillingness to leave Texas when I returned had something to do with the months that I traveled. I left in at the beginning of August, which is usually when the feelings from SAD start to affect me. Arriving in Texas, it was quite hot and sunny. Maybe my brain was processing the season a bit differently. It felt like it was spring there. Upon returning, I think there was that initial shock of it actually being winter where I lived. That actually caused whatever mechanisms in my brain to mix up seasonal-affective disorder to the point where I actually suffered for longer that year.
Perhaps that's the center point of your issue? Maybe the combination of your circadian rhythm getting mucked up - alongside the seasonal-affective disorder - has your brain trying to calibrate itself constantly without success? When you mention that you felt this way before in 2017, did you do anything specific to alleviate the symptoms or did they just dissipate on their own? Sorry I can't be of more use! Although, you seem to have a pretty firm grasp on your own psychology better than most, so here's to hoping that you've gotten a bit better since you posted this.