Keep your chin up and wait for your results via mail from the NREMT, which breaks down your score by subject category. You may only be off by a point or two! I HIGHLY recommend the AAOS study guide. If you have it, go through it again and again. If you don't have it, click on the link below to get it.
AAOS EMT-B Study Guide
You failed a test. Yeah, it's an ego check, but brush it off and take it again.
Best of luck,