If Christ has saved you, you are a member of His body and you have a job to do in His Church. You belong. You have something unique and wonderful to offer that the rest of the body of Christ needs.
We don't determine our giftedness any more than we determine our eye color. God has arranged the members of the body “as he chooses”. God decides, not us. It may seem obvious, but Paul makes sure his readers understand that we are all connected in Christ. Not only that, but we are gifted for a particular reason - "...for the common good" (1 Cor. 12:7). No matter what gift you have or what you think of the gifts given to those in the church, they were all given to build up the church, not divide it.
We were designed to need each other, but we are often tempted to feel useless or self-sufficient in the church. The root of both is pride, thinking about ourselves too much. And both viewpoints reveal a lack of trust in the wisdom of God.
In the Church, God's good design in that there is unity in the midst of diversity. The Church will not be known for its pastors. It will not be known for its buildings. It will not be known for its programs. Jesus says the Church will be known for how we love one another. (Jn. 13:35)
Despite what you think about the church, despite even the poor example that the church & its members have set at times over the years, God is calling you to be a part of it, to make it more complete, to operate in your unique giftedness, for His glory and for the good of the church.
This is all, as Paul puts it in 1 Cor. 12:18, “according to His design”.