Too many times in life we let the past stop us from our potential future. Most people can come up with so many reasons why they failed. Even if your 100% correct about what happened in the past it still doesn't matter at all. The past, due to its very nature, cannot be changed. All we can do is learn from the mistakes we made to do better next time. The future is all we have.
The future, by its very nature, we can alter. But we will lose this opportunity if we are stuck fearing unknown futures because of unchangeable pasts. That makes as much sense as to stop dating because one person turned you down. This is silly yet people do it every day. One person turning you down has nothing to do with the millions of men and women who you haven’t talked to yet. But how many people fear making that move because of what someone said to them yesterday? The answer is way too many.
You can't fight the battles of the past they are history. The only way you will build something new is to stop fighting that rejection, that slip, that failure that “devastated” you so much. And build something new on the grounds of that destruction. That is the only way you will see change. That is the only way you will move on.