If you have done something wrong more than likely it has probably affected someone else and has hurt them in some manner as well. Wronging someone can be a very difficult thing to deal with and it could end up scarring you and many other lives if you don't face it head on and take care of it. Probably the first thing you are going to want to do is to get forgiveness from those around you as well as God or whomever you believe is out there making eternal decisions. However, even after you have received that forgiveness elsewhere, it truly means nothing if you can't find a way to totally forgive yourself.
You may have done a lot of soul searching over a period of time finding the way and the courage to ask for forgiveness, you may have even taken that search for forgiveness to a priest and gotten absolution, which is what we are all looking for. But, you still need to search even further down within yourself and return to your own soul and face it alone knowing you've been forgiven from the outside world. Now it's time to be forgiven from within. There are some things that you can do to help you forgive yourself.
It is very important to realize that you have made all the steps to make amends, that you have confessed your sin and admitted it and others have forgiven you. Understand that you failed in the past but this is the present now and you can start fresh. So stand up and look around you and let what you did simply stay behind while you tell yourself to look forward. You have a life that is worth living and you need to allow yourself the liberty to do so by not allowing your guilt to block your from forgiving yourself.
Think about things that you have done that have been good and tell yourself that this is the person that you truly are, the loving and giving person that has done good things for their family and friends in the past. Convince yourself that you are worth forgiving, after all those around have forgiven you and you know that God has. If God has done this, then you need to realize that there is no one judge greater than God and if he believes you are worth forgiving, then you should feel the same way.
You need to focus on finding a time and declaring it to be the time in which you will fully and completely forgive yourself. If you can't do it today, then tell yourself on which day it will be that you will sit down and examine the reasons why you need to forgive yourself. This will be the point when you will be able to tell yourself to move on. Move on without looking back at your mistakes so that you can continue on your life journey, the journey that you deserve.