Sorry to hear that but this could be a great motivation for you. In my first semester of nursing school I BARELY passed my pharmacology class. I think I was literally at the cutoff for a passing grade. I had no idea how I did on my final exam but I was convinced I didn't get a passing grade. During break, I kept checking my email expecting one from my instructor for the class telling me I didn't pass. To my surprise, I never got that email and I passed. If I didn't I would have to retake that class next year and delay graduation. Because of that near traumatic event it made me change completely - my study habits, my outlook, and my motivation. The semesters after I studied so hard for all my classes and started getting all A's. I told myself I would NEVER put myself in that situation ever again. I may not have saw it at the time but that experience was a blessing in disguise. I do know a girl in my class that repeated another year because she failed that class and she felt like that was actually the best thing to happen to her at that time. She had a lot of personal issues going on and she felt that she needed to that to happen so she would be put on a slower track and so she can balance her school work and personal life better. So really...failing doesn't mean you are a failure, it just means you have another opportunity to do it better! You'll have that RN title after your name one day and 21 is still a super young age!
This is my favorite quote and hopefully this can help motivate you as well --
"Our greatest glory is not in never falling, but in rising every time we fall."