Consider this: Un-forgiveness is a heavy weight that slows your progress, easily upsets, and causes you to stumble, even when you are at your best; but forgiveness lightens your load, frees you to run the race of life more intently, and keep the pace without being held back.
Meditate on this: "Therefore, since we are surrounded by such a large crowd of witnesses to the life of faith, let us strip off every weight that slows us down, especially the sin that so easily trip us up. And let us run with endurance the race God has set before us" Hebrews 12:1-2 NLT)
Don't allow un-forgiveness to ruin your life and future. You can do so much more in your life without it.