“No man ever steps in the same river twice, for it's not the same river and he's not the same man.” - Heraclitus
Consider all the mistakes you have made in your private and working life. You have probably learnt, re-learnt and changed many times. You are not the same person as you were a year or even a day ago. There is no need to ponder past mistakes. Events and outcomes are external and can only reflect a moment in time, will serve you better if seen as learning opportunities. They have passed and are unchangeable, while you have the opportunity to learn, improve and adapt. Take responsibility and focus on the present moment.