Looking for advice on how to study properly and perform on exams

[Dylan Page]

Hey everyone, I'm currently working towards a Chemical Engineering undergraduate degree and I'm taking Physics II (Electricity and Magnetism), Calculus III, Biology I and Chemistry II. I am also working a part-time job to support myself. 

The inspiration for this post was a test I took today for my Calculus class.

Relative to most, I'm quite good at math. I'm always the one answering questions in class, I'm responsible and do my homework, show up to lectures, perform very well on quizzes, etc. 

However, on this exam, there were two questions that I was unable to answer. They were free-response questions that covered material we had covered in class before, but were either briefly discussed, or had strange twists to them, which under the intense stress and time pressure of the test, caught me VERY off guard. 

I genuinely put a LOT of energy into these classes and while I'm still learning how to be a good student, getting anything less than like a 95% just completely crushes me, especially when I'm putting in so much effort. While I think I'll be fine through school, and won't have too much trouble graduating, I would like to perform well, such that I could potentially go to graduate school. I believe I am gifted enough to do something useful in my life and would like to see that through. Everytime this shit happens, where I put in my all and somehow still get fucked over, it's like a knife to the heart. I'll improve over time, but I'd like to see if you guys have any study advice for getting through school. My coursework, at least for me, is quite time-consuming, and is mentally exhausting. I also lack intrinsic motivation a large majority of the time, and have to bully myself, gun to head, to get through some of the content. I sacrifice sleep and health to get all of my work done. 

There is a LOT more context to my life, and the factors that contribute to it, which affect my ability to study as well, but for now, I will leave it like that. 

TLDR: 

I tried my ass off studying for a math exam and still underperformed (Approx. a B). I am busy as fuck and cannot read the textbook three times and do 500,000 practice problems. Please, if anyone has any recommendations for navigating difficult coursework while simultaneously working and dealing with financial hardship, I would really appreciate it.