Anxiety is nothing more than our need to be in control or our lack of being in control of others! 90%+ of what we worry about never happens except in our heads! Haha
I own my own business and although most people wouldn't peg me as a control freak, as I lean more on the side of a giver rather than a taker. I do have anxiety, where I contemplate everything that could either be better or could go wrong.
I learned my lesson on my very first WDW trip with my wife. We were at the resort, she was getting ready and being a guy I showered and shaved threw on my clothes in 2 minutes and threw on a cap. I'm ready! LOL She, on the other hand was doing her makeup, her hair and was getting dolled up for the day. However, we had a Fastpass to get to and I started looking at the clock and doing the math in my head. The anxiety started to set in. She knows me well enough to read my body language. She finally looked at me and said, if you are going to be like this on vacation, you might as well have stayed home and worked! I thought about it for a minute and said, you know she's right. Missing a FP won't be the end of the world. I can always adjust the FP's to a different time. I learned a valuable lesson that day... Hey, I'm at WDW relax and enjoy, adapt and overcome! Enjoy the moment and who you are with rather than what you are doing and what you are getting done!
We have been to WDW many times since and I've adjusted FP's and ADR's and we switched entire park days the night before and we still managed to have a great time, because I learned to "Let it go!" and be in "My Happy Place!".