But this one thing I do--forgetting everything which is past and stretching forward to what lies in front of me, with my eyes fixed on the goal I push on to secure the prize of God's heavenward call in Christ Jesus. - Philippians 3:13b-14 (Weymouth New Testament)
We have all made big mistakes in the past but we are to repent, ask God to cleanse us in His Blood and put our eyes back on the call of God on our lives. You haven't messed up too many times and God doesn't take back that call. He's constantly waiting for us to get with it! So dust yourself off and get back on track with God!