None of your other accomplishments are truly analogous to skydiving. That's largely owing to societal pressures put on skydiving: no one gets told they're crazy for snowboarding, running, scuba or even flying. Nonetheless, I suspect the fact that you are accomplished in other "extreme"sports causes you to put additional and undue pressure on yourself to succeed. Know this: there are one hell of a lot of people who have amassed world records, stood on podiums wearing gold, and did other amazing things in this sport who sucked as students. That's a fact.
In the old day's I might have suggested a "relax" dive, you know, just getting out in the breeze, looking around, and pulling at the right altitude. For you, after two rides down, I'd suggest getting enough tunnel time to not only get basic body position right but also turns etc. When I say enough I mean enough that you get in the tunnel with a smile and get out with a smile. Then, if you're still of a mind, consider another jump