I don't know why I'm below average in almost everything. I don't know why I work hard at what I do but yet, still manage to yield the same, underwhelming results as others who don't put in as much effort. I don't know why my mastery of material doesn't translate to the kind of success people seem to get in courses so easily and on tests. I don't know why my ability to perform well on tests doesn't match up to those who don't care as much as I do, or who don't work as hard as I do. I don't know why. I just don't know why. There are many things in life that I just don't understand. And one of those things happen to be my comprehensive preparation for exams that I always think I do good on, but end up being either below average (which is usually the case) or not what I expect. I'm not angry at God for not answering my prayers and giving me the grade I wanted. I'm just unable to wrap my head around the idea that these experiences of mine seem to happen repeatedly, over and over again. Even when I submit myself to God in prayer and find hope in his divine plan for me and my future. I know God is in control, and I've given up all control to God, but I wonder if God is trying to teach me a different lesson. One I haven't quite learned yet or fully grasped. But what could it possibly be? What could it be? I've been overcoming sleep anxiety after having experienced a minor health scare a few months ago. But I don't think the lesson here is one of faith or humility. What is God trying to teach me?
Two pieces of advice and experience here. The first is about life in general, the second is about study habits.
When I was in college, my plans were to be a university professor. God had other plans for my life. In hindsight, I'm glad He steered me in a different direction than academia. During grad school, I picked up awards for teaching excellence and as a brief stint as a temporary professor, got above average ratings. I'd probably have been very good at it, but I ended up seeing a lot more of life and learning a lot more about being excellent at what I do than if I'd stayed in (what I now see as) an artificial bubble of life of academia.
Stepping back to look at the big picture of life, I truly believe that God has made you (and each one of us) to be a unique person meant to reflect His glory in some way that no one else can. Life is not about finding a niche where we can excel, it is about being the person He created us to be and walking with Him. I spent decades of my life trying to excel as a husband, father, Christian, in my career, and trying to be a good steward of my gifts and talents. For the most part, I was probably a good example of what a Christian was supposed to be. In doing this however, I made my identity into those things; I measured myself by how well I did those things. I was in my mid 40s when God finally pulled me out of my self-imposed rat-race and helped me realize life was more about being than doing. He took me on a couple year journey where He started showing me who He had made me to be. I found that life became easier and it was like things just started naturally flowing out from me. My gifts and talents became tools to use rather than a reason for living. Life feels so much easier now and I am accomplishing much more than I used to. It's like stuff just flows naturally now rather than being work.
Since then, I've facilitated a number of small groups which were about finding out who God made us to be. I found that most people have gotten so used to putting on masks to fit in (with family, church, school, jobs, peers, various social circles, etc.), that we forget what our own face looks like. I found many people who are dissatisfied with parts of their life were unaware of who God made them to be and were striving to accomplish things that were obligations, duties, expectations, and going with the flow rather than living life as the person God created.
Onto the second topic, everyone has different ways of learning and studying that are more effective for them. Sometimes frustrations in learning speed in particular subjects are due to inappropriate and ineffective methods rather than being "less gifted".
I was always interested in foreign languages, but frankly sucked. I got 2 years of As in college German but about the only thing I could do after that was ask where the bathroom was. I tried to learn Greek for reading the NT, but in 25 years of on and off efforts, the best I could do was work through a sentence or two in an hour or two of work. A ton of work at German, and I could use it for simple e-mails with colleagues in Europe, but that was it. God brought me across a number of online language learners and I studied their study habits. I realized that my problem was that I was using the one method I learned in school which was rote memorization and brute force study (which is what got me As). Successful language learners mostly practiced real skills using a wide variety of study methods. When I started doing that, my language accomplishments skyrocketed. I'm now on my 4th time through the Greek OT (LXX), probably my 10th or so time through the Greek NT, I started learning Spanish about 2 years ago, am on my second time through reading the Bible in Spanish and can comfortably watch Spanish subtitled shows on Netflix. Just learning how to learn took me from banging my head against the wall in languages to actually being able to use them a fun part of my life.
Depending on the subjects you are struggling with, this might be primarily due to using ineffective methods of study.