Learn to Live in the Moment, not in the Past
If you want to be successful in your business and in your life, you have to turn your attention to what is happening for you right now.
The past is history - there is nothing you can do to change anything that has gone before, good or bad, and so, you must turn your attention to the here and now.
If you have regrets about the past, you can't undo what's done. If you are hanging on to guilt - the only person you are damaging is yourself. Everyone makes bad decisions and the only positive thing to do is to resolve not to make such bad decisions again: acknowledge where you messed up and try your best not to repeat the pattern.
If the past was better than your present, then learn to appreciate the memories, but move on and put your efforts into finding a different good life now. Leave the good stuff behind and find new challenges to inspire you towards to new life.
Every day is a new day to make a fresh start in your business, so make it what you want. Dig deep - find the enthusiasm, dedication, concentration and perseverance to create the business and life you want.