I agree. As long as you're happy more often than not, you're doing well. Ups and downs are natural in everything and you can't appreciate the ups as much without the downs.

you wouldn't be where you're at today without all of the decisions you've made

You make an excellent point. Regret can certainly eat you alive. If we are able to objectively observe our own past, we can uncover hidden lessons from these regrets. There was some reason for this "wrong" choice, and like you said, every single decision you've ever made is what defines you and your current place in time.