I literally sobbed hysterically (in the privacy of my bf's apartment) before my first two tests...
I think that every new medical student has this moment of mental and emotional anguish. I'm pretty sure that most of my classmates have broken down at one point or another. I know that I do before every single exam - except, instead of crying, I react by freaking out and staying up all night cramming. (I did cry once last year, during neuroscience. I've never been so exhausted in my life). Just do what you have to do - flip out, cry, stress, throw things, yell, scream, whatever it takes, but once you're done, get on with it. The sooner you have your meltdown and get it over with, the better.
Medical school will constantly push you to your limits. And, just when you think you can't go any further, you realize that you have to. That's when you muster the strength you never knew you had, and you just do it. To be honest, I did not walk into a single test last year feeling prepared. Not one. It's a horrible feeling, walking into an 8am exam, having gotten 1 hour of sleep the night before, shaking from all the caffeine you've had, knowing you've got to pull it together for at least the next 3 hours, and feeling like you are going to bomb and fail and get kicked out of school. But, I swear to you, every time this happens, its the same result every time - it turns out just fine. I finish in plenty of time, get my score, and realize that I've passed on to the next phase. Then I feel really silly for stressing out so much in the first place. This probably happens to a lot of people.
As long as you see all the material presented in your lectures at least once, I'm convinced that you'll pass (not "you" specifically, OP, but in general). Depending on what your own personal goals are, how much more you do on top of that is up to you. If you can do this, you will NOT flunk. You may not get an A, but you will not flunk. Concentrate on seeing everying a minimum of 1 time, and then build on that.