Trying to find your purpose in life outside of God can possibly lead you to listen too much to the opinion of others. Trying to live up to other people's expectations can lead to heartache and disappointment. On the opposite end of that is living your life in the light of what God expects. His ways are higher than our ways and He wants good things for us.
Take your focus off of yourself and focus on the love that God has shown and allow Him to lead you. You may have made massive mistakes in your life, but that doesn't mean that you cannot pick up the pieces and still find purpose. Another quote by Rick Warren... “we are product of our past but we don't have to be prisoners of it.” Thank the Lord God's love covers a multitude of sins. So often mistakes have a way of making us feel like we are failures. It is during those times that we need to draw our attention back to the love that forgives and forgets...the love that was there before the creation of the world. There is no greater Love!
The character of purpose is being in the center of God's will and understanding that no matter what the circumstances of your life...if you love God, good can come out of all situations.