@Lifelong_sinner Friend, you speak of unrest and fear.
Since I can relate, I will share a part of my testimony with you. It begins with me being sinful and hungry for God's Grace, and ends with me resting as I look away from myself and instead unto Jesus.
One day I found myself realizing I had a head knowledge of Jesus, but no experience. No conversion. I didn't even have conviction of sin. I knew I was missing *something*, and I knew that something was Jesus.
By God's Grace, I prayed for Him to bring me to Jesus, and that I would see my sinfulness. So He answered my prayer and put me in my place, but it wasn't easy for me. Some people speak of having a wonderful, easy conversion. That wasn't the case for me. In my case, it is as if God Himself grabbed my heart with a clenched fist and drug it through the deepest torment imaginable, in order to build me up on the firm foundation which is Christ. I have been greatly blessed in many ways, but I'll keep this short and share the basic structure.
First, I was shown my sinfulness...and I was tormented for years. I was frustrated, doubtful and fearful. This ruled my mind. But my doubt wasn't in the Diety of Christ, it was in my Salvation.
I couldn't accept not knowing if I was saved. So I convinced myself that I needed to make something work within my mind to convince me that I was saved. I was trying to grasp something. I needed to grasp something. A N Y T H I N G. I was searching for a phrase from the Bible that would undeniably assure me I was saved. So I studied and studied and studied, and I considered these verses and those verses. I will say, there are many wonderful verses for all of our problems! But doubt always crept in my mind. In my heart, I was always able to say, "Perhaps my heart deceives me, and I don't genuinely believe on Jesus." I knew if this was the case, then I wasn't saved. I was in a vicious cycle. Who can stand the thought of burning in hell for eternity?
I worked at it for years, but my hands would never bring me peace. In fact, my hands will never bring me peace. Neither will yours, or any of ours.
Finally, I heard a dear preacher say he wasn't going to do try to do anything for his salvation. He was going to simply trust in Jesus Christ, that He did the necessary work for his salvation.
Boom. It clicked in my head at that moment. I'm going to trust Jesus. No longer will I try to rest in my understanding. Now all of my hope rests in Him. I have peace. Christ is all. Done.