I competed at a professional level in motorsports and had a lot of momentum in my 20s. It felt as though I was headed to the top of the sport, but it came to an abrupt end from a rare medical condition. I struggled for several years to come to terms with not knowing what could of been and probably had some minor depression because of it. It took a lot of self reflection and time to realize that I was extremely lucky to experience what I had, and I had so much to be happy about in the present.

That being said, there is a Limitless episode with Chris Hemsworth that might resonate with you, especially regarding martial arts. Watch season 1, episode 6, called "Acceptance". I had never watched any other episode of this show, but late one night when the whole house was asleep I was browsing and came across this episode and thought "hmm, looks like a good bedtime show". Ended up watching it and you'd have thought someone was cutting a thousand onions in my house. In fact, our Golden Retriever turned into a service dog that night hah!