I'm not super type-A though, am more of a generalist than a specificist, so it could have been a lot worse. But being prone to anxiety and having been trained in the art of worrying from a young age (a habit learned from my father), I can say that at the root of such struggles, when you drop down in the well, you find the issue most prevalent revolves around control. Loss of control can be an nauseatingly fearful thing. The Israelites were constantly falling into the trap of not trusting God and preferring the illusion of control that idols and false gods gave them.
I certainly fell into the trap early of the self-reinforcing "worry trap": if you worry about something enough, you can change the outcome. When you worry about something and the bad thing doesn't occur, it reinforces the erroneous thinking that your worrying is what prevented it. And so you learn that worrying can change things, when in fact nothing could be farther from the truth.
I tend to believe that worry, anxiety, fear, and scrupulosity are all cousins. Early in my conversion, I struggled with scrupulosity of the religious type. The priest who instructed me in the faith and the catechism as not a particularly healthy (psychologically, emotionally) man. I remember the fear of being hit by a bus before I would make it to Confession, and living in the fear of Hell. Religion is a poor antidote to such dispositions when it is not accompanied by a real relationship with the Living God.
Over the years such scrupulosity melted away and was not as much a struggle for me. I think this was in large part due to grace, to a deepening prayer life and friendship with the Lord, and also in meeting me wife, who is as Type B as you can get. Loosening the reigns on feeling I had to control everything was aided by having children. I distinctly remember when my daughter was born and feeling overwhelmed at how to raise two kids. I drove to a Wawa while my wife and newborn baby were asleep at the hospital, sitting outside my car smoking a cigarette and just saying to God, "this is too much. There's too much that can go wrong and if I think about it or worry about it I'm going to go crazy. So you take it. I'm turning it over to you." Because we believe in a loving God and Father, we can do this in full confidence that He WANTS to drive for us, wants us to trust Him. His yoke is easy, and his burden is light.
As my own scrupulosity gave way to trust and confidence in God providing for us, I had a friendship with another guy who suffered from religious scrupulosity as well. He struggled with sin, as I had, but also in feeling forgiven. He felt, erroneously, that God was tired of him and tired of his crap and just didn't want to be bothered anymore and that he wasn't worthy of God's love. I gave him information about Scrupulous Anonymous and encouraged him to reach out to them. Unfortunately this also translated into our friendship, and I felt there became more and more distance between us. When I finally brought it up to him, he confessed he didn't feel "good enough" for me or worthy of our friendship. I tried to reassure him that wasn't the case, and while I felt hurt I respected whatever distance he wanted to maintain and we eventually fell out of touch.
There is a kind of hellish neuroticism in scrupulosity that wants the lock-tite assurance of being saved. It is also a tool of the Devil. I think Martin Luther had these kinds of OCD tendencies and this motivated him to develop his theology of justification. As a Catholic, I trust in the mercy of God. I trust that I have been invited to share in the Heavenly Banquet but that this does not depend on anything I can accomplish on my own. And yet, I cannot just sit back and not cooperate with grace. I trust that I am saved, I am being saved, and I will be saved. That freedom, when it trusts and is based in the confidence of a child for his father, and is motivated by love rather than fear, has the potential to burn away the restricting sterility of scrupulosity when it is the presence of the burning Sacred Heart of Jesus.
Salvation is not a human endeavor, but is a gift that rests completely on the goodness of the Giver. Christ as man both human and divine synthesizes this need in our human economy as a counter to the rote Law and the limits of wooden idols. He became fallen man so that we might become divine. Spiritual health requires moving beyond mental obsession or spiritual fixation and invoking the heart, the mind, the body, and the spirit in synthesis. This is what makes us human beings able, in freedom, to fall rather than test-taking robots. The Devil does not want us to trust our Father. He does not want us to live in love, but in fear and servitude. He is a legalistic and will flex the Law if it helps him in his purposes. Don't let him. Relish your humanness, know that you can fall but trust that God is greater than your sin and failings. Exercise your will in a way that offers your choices as a gift, an oblation to God, in loving obedience. Trust in the unfathomable Divine Mercy of God in Christ. If you struggle with scrupulosity, I pray you will grow in love, trust, and confidence so that you can leave behind such mental legalism like a cicada's shell, a snake's skin, and just rest. It can be hard to rest in Love. But once you have, you know there is no place better to be as the antidote.
"I know longer fear God, but I love Him. For perfect love casts out fear (Jn 4:18)."
--St. Anthony the Great.