For this type of accident to be covered, your GMC pickup truck would need to have collision coverage. Collision covers damage to your car when your car hits another vehicle or object, such as a tree.
To file a claim with your insurance company contact your insurance agent. Soon afterward you should be contacted by someone from the claims department or a claims adjuster from the insurance company who will want the details from the accident. They will determine if your truck was covered under your policy terms and continue to work with you until the claim is settled.