It's Not Natural

Went to Go Ape with work today; a team building day.
Have never felt fear like it. I really didn't think I would feel that way. I got to stage two and had to zip wire into a cargo net. Just couldn't do it. The instructor was coaxing me on, but it just didn't feel natural to throw myself off a platform along a zip wire over to the cargo net like this one.
Took me about 5-10mins to do it, crying all the way, then had to walk across 15-20 logs to get to the next platform.
It was then I decided I couldn't do the next three stages. Each stage went higher and higher.

Got down to the ground and gave up. Took harness off and joined other colleagues. I went chalk white and nearly passed out, a colleague having to catch me as my legs buckled under me.

This is one of my colleagues ; the first one in line and she just went for it!

Hours later I still feel jelly legged and sick. I am such a failure. I hate myself right now. Can't do anything right.