Preparation is key
Everything in our yesterday was preparation for our today. But, we probably were not aware of this truth or its far-reaching significance. If we were, we would have maximised our opportunities for learning and reacted differently to the situations we faced. Now, yesterday is gone and we are left with the fruit of our actions (and inaction).
Before regret and self-pity kicks in, understanding of this same principle can still work for us, because today is preparation for tomorrow. Everything happening to you now, with all the opportunities for learning and gaining wisdom, is preparation for your tomorrow. And you cannot say tomorrow that you were not aware of this principle yesterday!
Welcome every experience as God's way of growing and preparing you. Does not all things work together for the good of those who love God and are called according to His purpose? Everything is for a purpose; with God, nothing is coincidence.
Submit yourself, therefore, unto God and He will lift you up in due course (if you have taken time to prepare)...