I have an irrational fear that is ruining my life
What makes you feel so afraid?
I'm always afraid that I'm going to fail, like the test I just took.
If the fear of failing is that debilitating for you, you need to get some professional help.  Hopefully they can help you work through these issues!
But I don't think that would help.
I know it seems scary now, but a therapist or other professional is trained to deal with the problems that you're having. If you ask them to help you, I know you'll be able to overcome your fear together.