This life flies by quickly. I know I would rather live each day looking forward instead of thinking about what could have been or how I messed something up in the past. You can only look one way at a time...if you are looking back at what you have done, there is no way you can focus on the future. We can't change the past, but we do have some control over what is to come. Focus on what can be, not what was.
We need to extend these thoughts to the people around us, too. Don't hold grudges and remain angry for what someone did in the past. If you keep them in your life, forgive them and move on. Even if the person is no longer in your life because of what they did, forget about it. Dwelling on the past only stops you from pushing towards the future as much as you want.
Life is going to be difficult, but it is a little easier when you focus on what is to come, instead of what has happened. Each day is a fresh start...take a deep breath and keep pushing forward.