Once you reflect upon old concerns and worries, and learned from them, it's time to bury those old concerns and worries--time to start anew.
Life's events include some that are surprising, worrisome, and filled with regrets--these are the moments in life when you misjudge, are caught unaware, or face unexpected hardship. Essentially, these are the problem spots in life. Sometimes you may not even know why these events happened or how, but nevertheless, to think back on them creates concern. It is important to learn from these events, then move forward.
Unhelpful
There are likely some people or events that proved to be unhelpful to you. Sometimes we don't even know what a person or event is problematic or unhelpful--often it's the result of chance when two lives connect in less than positive ways. It happens. Learn from these events and move on.
Challenge and Struggle
No matter who you are, you will face challenge and struggle in life. This is part of the fabric of life. Again, do the best that you can with these challenges and struggles, learn from them, and move on.
Good times
Consider the good times--the events that filled you will joy, happiness, and contentment. Replicate the conditions that created such good times as often as you can.
We can't stay mired in the webs of old concerns and not-so-good events, instead we have to move forward with greater wisdom and will to create good times.