Hello, Tiredofself!
I can identify with what you described! Sometimes, being under such pressure, anticipating a big important test, can actually cause you to shut down. Especially, if you have obsessive compulsive tendencies.

In my years in college, I found it very hard to focus, though I loved being there and appreciated the opportunity to learn. One year, I could NOT stay awake, slept all the time at irregular hours. Looking back now, I realize I was suffering from major depression, but that was many years ago, and there was no resource like counseling or medication.

Later in life, going back to college, I learned that I have to take study in small disciplined increments. I'm pretty sure I've always suffered from Attention Deficit Disorder, though I've never been diagnosed.

I agree with the others here that a counselor might be helpful to you.
Perhaps you are in a form of depression, or, like me, some sort of attention deficit. Or maybe you're just overwhelmed!

I learned later in life that I had to limit the amount of classes I could take in college. Sometimes, just one or two per semester, since more courses overwhelmed me.