You are definitely not a failure. When we are struggling or fail a test, paper, even a class we are still learning. Sometimes what we learn is that we need to change our approach to studying or we need extra help.
Have you contacted the instructor or a school guidance counselor to get another opinion on what you can do to get things turned around in these classes? That would be a great place to start because it also shows them that you want to do well and you are seeking out their help.
If your school work has been a problem only recently, there could be something else going on.
Sometimes other things in your life make it difficult to concentrate on your studies--problems at home or with friends.
Whatever the case may be, reaching out for help from those who know you and can help is important.
Grant, Hotline Counselor