When I was in high school I had bad depression, along with that I also had social anxiety. Multiple days I recall going home to cry, or punch my wall out of frustration. I had an incredibly low self opinion of myself. Because of this I decided that I should start going to the gym, and eating healthy because I thought that if I couldn't be strong on the inside, that at least I could try to look strong on the outside. The fitness journey that I started got me out of that depression rut, improved confidence, and made me grateful beyond belief. Studies also show that exercise can combat against this type of thing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3674785/
I had issues that exercise helped me work out (caught the pun?)
It is amazing how exercise not only works on your brain chemistry the moment you do it, but a much more complex effect involves: better self image, boosted self esteem and confidence, not to mention that it helps you become more sociable (at least it helped me).
I'm happy to hear that it basically changed your life to the better! Have a great day!