I'm happy that worked out for you. To be fair, however, moving from the US to Norway has done wonders to help with mine. But I understand that could easily be that outside stressors are different and I'm in a much more stable and healthy environment than I was previously. I'm also in a situation that I chose. All of it, all of my everyday life is in a situation I chose. I also rather like being an immigrant, it turns out. I'm going to guess you have some of these feelings too.

Not everyone can say that.

And as it turns out, my experience about beautiful days is different from yours. I find it is quite easy not to feel good on a beautiful day. Doubly so if you feel too ugly to go outside, better about yourself when you can wear a jacket, if you are in a bad situation, stressed, sick, stuck, and so on.

Seasonal Affective Disorder (SAD) is its own thing, and yes, bright sunlight or artificial sunlight is the primary treatment.