If you haven't had one yet, trust me, you're going to get a test in the next four weeks.
Don't stress. Don't freak out. Don't be scared.
It's not a test: It's a pat on the back. You can choose to focus on your mistakes. Why not focus on what you did well? If your class doesn't have a cutoff point, why is 80% a failure?
It's not a test: It's a diagnostic tool. The questions you got wrong are not mistakes. They're a way to analyze what you need to study more.
It's not a test: It's a reality check. Sometimes, it's not very pleasant to see your errors in black and white (and red) in front of you, but it's better to know NOW, while you can still do something about it.
Remember that a reaction is always a choice. How you choose to react to a test -- and your test results -- can determine how well you'll do in your English class this year.