Kindly allow me to share my experience with you.
I grew up being told almost every day that I was special, smarter, and destined for great things. At school, I always aced every exam possible. In my mind, teachers could only give me A+ or F, there were no other grades, whatever the matter: math, history, English, phys-ed, etc. But outside school, I always felt average: neither attractive nor ugly, neither talkative nor shy, neither stupid nor smart.
Then came high school, and this decisive moment when I was supposed to know what I wanted to do. Some wanted to be doctors, I thought I was not capable of becoming a doctor. Others wanted to be lawyers, but I was never attracted to that world. Science? I didn't realize I could have chosen engineering, or some STEM faculty, I just didn't think of it. Nobody told me I could go there either. I studied economics, it wasn't hard but I felt outrageously bored. Year 2000 came, I noticed people could earn good money doing websites, so I bought some books and gave it a try. From that moment, IT jobs came one after another: always well paid, somehow interesting. I was never bad at them, nor brilliant. Years passed rapidly.
When I think about it: no one ever told me how to be successful or useful. And no one "pushed" me under the train to something big. Maybe this could be your issue? I often envied those who get it, who actually "do something" with their life. I never solved this problem. I even tried volunteering: serving soup at christmas, spending time with children in hospitals, becoming a monitor during summer camps for socially disfavored children, tutoring students with their homework, I always had the same answer: "you're too late, we don't need more people".
I noticed a lot of people around me, especially at work, always get things taught, coached, mentored, etc. I never landed a job where my manager just dropped me into some training or certification course. I always had to figure out things by myself. One time after I was named manager, my boss refused to pay me some training. A few months later, a colleague was promoted to the same position, he ended up in a 3 weeks leadership/management program, all paid by the company. I asked my boss why i didn't the training, her answer was simply that she didn't think I needed training.
I often get invited to speak at conferences, I even was invited as a keynote speaker. I refuse. I am not scared of speaking in public, I just don't have nothing particularly interesting to tell.
Starting your life being told you are "special", "smarter", or whatsoever puts a lot of pressure. For more than 30 years, I think my parent's way of telling me they believe in me just made me feel like a complete failure, and prevented me from ever feeling happy with who/what I am. I do nothing very well, I am not very intelligent, it often takes me more time than others to understand all the intricacies of a social situation. In society, I struggle when I must interact with fake, selfish or imposters (and there are many).
One day, I realized I was "mediocre". My parents are/were even more mediocre than I think I am and my hypothesis is that they saw me as smart because they were mediocre. This realization freed me. I started forgiving myself and became more benevolent towards others. Being told you are a "10" and feeling like you are a "5" is agony. Realizing you are a "5" and feeling you may live as a "6" made me see life completely differently, and much more positively.
All things considered, it appears I do well enough for a few people to thing I am worth their consideration, their attention, sometimes even their friendship, and ultimately, their love. I have good friends, I love my family, I love my wife and every minute I spend with her. I have a respectable job, a nice boss, nice colleagues, etc. Since I accepted my "fate", I generally feel much happier in my life.
I sometimes have bad thoughts about my wife: I feel sorry for her. She is beautiful, smart, independent, funny, clumsy in a lovable way, interesting. She is clearly above my rank in most aspects. But she doesn't seem to notice that she could do much better than "me". Along with the mystery of how to do something with my life, I guess her living with me is the second big enigma in my life. But apart from this, all is going well.
I noticed that once you start looking at the "grand picture", whatever the potential you reached or the "productivity" you achieved throughout your life, everyone of us ends up exactly the same way: dead. I calculated that I have ~2'000 weeks (assuming I die old) left to live. It's my countdown, it is brutally honest but honestly, why should I care about being successful when I only have 2'000 weeks left before I die?
My advice: just try exploiting your potential so that you can live with dignity and healthily. If you can provide shelter, clothes, food to the people you love, if you can resort to violence when it is ultimately necessary, and you can afford to spend some quality time with the people you love, well, in my very insignificant opinion, I would see you as a highly successful individual.
If you find the way to make other people's lives better without sacrificing yourself or the ones you love, then, yeah, why not. Otherwise, just enjoy the ride. I honestly do not thing life is worth torturing yourself about whether or not you accomplished something.
Those are my 2 cents. If only 1 sentence of my experience can improve your opinion about yourself or your life, then I will consider this day as a successful day :)
take care.