When you were saved, you became a new creature in Jesus Christ. (2 Corinthians 5:17) As a human being, your primary identity is your spiritual person. We were created in the image of God. God is a Spirit. (John 4:24) God is also a personal being with a mind, will, and emotions. So when we were created in the image of God, we were created as personal spirit beings who live in a body.
C.S. Lewis correctly observed that man is not a physical being who has a soul, he is a soul who lives in a physical body. Our body is the home that houses our spirit. The apostle Paul confirms this in 2 Corinthians 5 when he refers to his body as a "tent", a "building", and a "house".
Jesus taught in John 3:8 that the Spirit is like the wind - it is an unseen force with tremendous power. When we were originally created by God, we were spiritually connected to Him so that His Spirit was the energizing force behind our mind, will, and emotions. When the human race fell into sin through the temptation of Satan, we died spiritually. That is, we lost our spiritual connection to God and became connected spiritually to the realm of Satan. So now Satan and his fallen comrades are the energizing force behind our mind, will, and emotions. This is described in Ephesians 2:1-3, and it results in a life characterized by "indulging in the desires of the flesh and of the mind."
When one comes to faith in Christ, they are united with Christ so that this spiritual connection to the Satanic realm is broken and our connection to God is re-established by the Holy Spirit who comes to live within us. So now the Spirit becomes the energizing force of our mind, will, and emotions.
Unfortunately, Satan and his cohorts had plenty of time to corrupt our brain. Romans 7 gives us a vivid description of the struggle within. Paul identifies the source of this struggle as being in the members of the body. Obviously we know in our day and age that the brain operates like a computer does. It stores information and controls our thinking processes.
Since our brain has been corrupted, the remedy lies in the work of the Holy Spirit to transform us by "the renewing of your mind", as Romans 12:1 & 2 says. It's like pouring clean water into a glass of filthy water. As you pour the clean water in, the filth is flushed out and what is left in the glass after a while is clean water. The water in this case is the teaching of the word of God. Paul tells us in this passage that we are to first present our bodies a living and holy sacrifice. This simply means you need to make a full on, 100% commitment to Jesus Christ with no reservations. Secondly, he says, "do not be conformed to this world". You must separate your self from the influences of the sinful culture we live in so that it's values and thinking do not further corrupt your mind. Thirdly, we are to be "transformed by the renewing of your mind". This of course is saturating our mind with God's truth so that our thinking and our mind is transformed into the likeness of Christ, and hence our behavior becomes more like Christ.
This is God's plan and will for the Christian life. The result of this will be that you will express this Christlikeness is the exercising of the spiritual gifts of service that God has bestowed upon you, as described in Romans 12:3-8.
You are a new person in Christ. You just need to get your mind and thinking in line with who you really are spiritually. If you do, the grace of God will transform you into the person you really are.
God bless you, friend.