Having difficulty dealing with the idea that I might not be unique or special?

I've always been a particularly bright person. I did well in school all throughout high school. In college, however, my grades became average or lower than average because I started focusing elsewhere. The reason I started focusing elsewhere was because it was when I got to college that I realized that I had a very powerful subconscious with which I am in good communication. I've never thought that I have it all figured out, or that I even have myself all figured out, but I've been under the impression that I'm on a better track than most people. My reason for thinking this is because I have a very powerful problem-solving mind and I spend a lot of time thinking about deeper things, such as why people do the things they do, why I do the things I do, and how might I better adapt to fit in? I spend a great deal of time thinking about psychology. One of my greatest intrigues is the difference between the self and the persona, or a person's true self and the person that someone is in for others. I've always thought that the majority of people don't think about these things, but I'm slowly learning that everyone thinks about the same things as I do, whether it is on a conscious or subconscious level.

Now I've always understood that I'm not unique, that I'm not the smartest person in the world and that there are others out there like me. But I'm having a very difficult time accepting the idea that pretty much everyone is the same and anyone is intelligent on some level, whether it is in interpersonal interactions or philosophy. The problem with this is that I am capable of doing great things given my problem-solving mind. But my abilities are proportional to my confidence, and learning that anyone can do what I do has crushed my self-confidence and motivation at the age of 20.
The thing that enlightened me most to the fact that anyone is capable of higher levels of thinking is body language. After learning the intricacies of body language, and how people might say one thing but think another. It made me see that my assumptions - that most people don't think on a deeper level and that most people are not inquisitive and do not constantly examine their world like me - could be terribly wrong.

I don't know if I'm just overreacting and I am still on the right track or ahead of the game, or if I truly am just more vocal about my innermost and deepest thoughts than most people.

You have used the word "I" means ego there is no answer.

It just means that your blessed. Don't fall under the impression that this life is the only one youl ever know. You will be unique again and again.

This is ego speak.  Pride is sooooo good.  As the character Avi said in the film revolver, "You have got to admire the opponents elegance".  He is so good that he will feed off of the very introspection that is intended to minimize him.  This is like getting fat off of diet pills.  But he is also very timid and easily provoked.  This lets you know it is him.  When you feel that burn, it is him.  When you feel that fear, it is him.  You are feeling it now so there you go, it is him.  That is not the you that you have been searching for.  Jesus said turn the other cheek.  This applies to more than just being slapped.  An angry reaction to being slapped is him, ego.  So turn the other cheek and the next slap will not strike you, it will hit him.  Good luck.

"I'm slowly learning that everyone thinks about the same things as I do, whether it is on a conscious or subconscious level."

Yeap. Even the ones you thought were kinda not that bright? Well, they have something to teach you. Basically everybody has this epiphany as they enter the adult world.

Humility, I think, is a thing you should embrace. It's a positive thing, to stop comparing yourself to others, and instead think of them as peers who can teach you something, and for whom you can do things too. Your self-confidence and motivation should not have any roots in your belief that you're superior, so re-cultivate it without that illusion.