Any advice for someone who can't really accomplish anything with his skills?

I'm a CS student, and since I started I've always tried to be a step ahead when it comes to my skills as a developer. I often study on my own and I feel very accomplished when I learn new programming techniques and what not. My dream has always been about developing videogames, so in January I bought a course about videogame development with the Unity engine. Like with college, I blasted through it and many times I even skipped videos because I already had implemented the mechanics they were teaching, and some times were even better solutions that the ones shown in the video lectures.

I know I have strong skills and a strong foundation, but I can't do NOTHING with it. I try to come up with game ideas, but I get afraid because it gets really complex sometimes. I see how developers do marvelous works of art and sell games that get critical acclaim; yet when I try to get something done I feel like I know nothing.

I know so much and I can't apply it at all because I get scared to make a bad product, and that gets on my nerves. I want to succeed, I want to work on something to be proud of but I can't do anything right. I feel lost and sad many times, like I'm some kind of low life, meanwhile other developers that are much better than me continue making awesome things. I don't know what to do anymore. Many times I feel like giving up...