College is hard.
There are hundreds of pages to read, tests, quizzes, and projects that all have an amazing ability to end up within the same week. It can be overwhelming and daunting, and honestly, it's the part of school that no one really prepares you for.
What I have found is that balancing social, academic, and other pressures that school brings is beyond stressful. It takes time to understand what you need and what processes work the best for you.
There is no need to compare yourself to the girl next to you in class who read her study guide for one minute and got 100% on the test. In reality, she is probably lying, and if she isn't, that just isn't the best system for you.
My first week in school I remember feeling overwhelmed with the amount of reading and responses I needed to submit. My sister kept saying you will figure it out. I couldn't see past the 500 page textbook in front of me, but sure enough, I did figure it out. I learned what I needed to read closely, what I could put off for another time, and most importantly how to make a study guide that actually worked for me.
Fast forward to now, and I have completed multiple tests, papers, finals, and readings. I know that talking about what I am learning works the best for me, and that starting a paper early enough to revise two, even three times, is best.
But these are just the things that work for me. I know for a fact that these don't work for my sister, roommates, or even the stranger sitting next to me in lecture.
People learn from their mistakes. It is something that we have been doing since we are young, and while it can be difficult to fail I am pretty confident that a mistake will ensure that you don't repeat it in the future.
So accept failing and be okay with it. Try new things, and find what works for you. Block out what other people say.
It is one bad grade in one random class out of one hundred. There will be another time for you to do better, and there is nowhere else to go but up.