I know you feel like you are the biggest failure, but honestly some people are just not good testers. That doesn't mean you are unintelligent. Tests are typically designed for your "average" person. They don't take into account different learning styles, which vary from person to person. I know this is obviously much different from your average high school exam but the same principle can still apply. I know it's hard, but try not to beat yourself up for it so much. You did your best and there are always more chances and more options out there.