Remember: You are awesome. Don't stress.
I'm a grad student who works with undergrads right now. I know at a lot of universities it's midterm season for undergrads! And many of you are probably feeling really stressed out, perhaps helpless, maybe a bit out of your element for the first time ever in your lives.
I just want to say you are awesome. Don't stress. Your self-worth isn't determined by your classes or your professors. Your worth as a human being doesn't boil down to your grades or what you get in your class. And many a successful business person/graduate student has failed a midterm, failed a class, even gotten a sub-3.0 GPA in undergrad. Trust me, it is definitely not the end of the world. I am not saying this to trivialize the experience - it can be traumatizing! - but to assure you that you will be okay, and that your success does not hinge solely upon your performance on this class or even in this whole semester. If you weren't smart and accomplished you wouldn't be where you are now - in college - so take a moment to reflect on your positives.
I also want to encourage you to recognize that your professors are humans, too. They know stress and frustration and struggle with concepts. If you are feeling overwhelmed, please talk to them, or to your TA. If you are feeling so overwhelmed and you can't cope, please go to the counseling center at your institution. They are typically friendly and awesome and waiting to help you, and there's nothing wrong with it - probably 30-50% of your peers are going, too.
Good luck on your exams, and enjoy your spring breaks!