Most of you have managed to get through this. How?
Can you try to recreate the real test environment and take practice tests that way? Time limit, location, mood, no music or headphones etc. Treat your practice exam as if you are writing a real one and do this over and over again.
Don't stress about or study for the test. Your studying should be to learn the material, your practice to master the techniques. Then, when the test comes, it's just like doing any other assignment.
- A. Techniques focusing on the circumstances: It's not your fault. You have shared, objective evidence that shows that testing circumstances are a problem and that you know your stuff. So, for these techniques, you take an objective view and go to your profs and say "look, here's the situation, I need help, what can be done?" Keep an open mind, and see what they say. (Please don't stop with just one person--Ask a variety of profs, ask department leadership, ask around) I've seen some great examples where students were accommodated really well.
- B. Techniques focusing on you: Check for a resource lab that can help you out. For example, test-taking courses. These treat the test-taking process itself as a skill that can be mastered. You can even find these on Youtube. Some schools also offer self-hypnosis courses. These also exist online and there are test-taking scripts on Youtube. A lot of people will lecture you on these techniques but it's important to ask: Which ones seem like they would help?
If you can, I recommend putting most of your effort in group A. It's not a cheat, a weak path, or a shortcut, it's just getting help you deserve. People do this every day, and your school and department both probably have resources.
Also since your school works in levels / shells from you up through your department, feel free to ask your school's general counseling center as well. They have definitely been through this a thousand times with various students. They can often point you to objective resources and suggest methods.
Anyway, I guess what I'm saying is--there's probably some immense pressure to blame yourself. Instead, please help yourself in as many different ways as possible, without blaming yourself, if possible. Good luck & hang in there.
Also, many professors will create test questions inspired by the end of chapter problems in your text. Try reviewing them, specially the ones not assigned, before an exam. It might help reduce your test stress by not being caught off guard by a test question.
Being prepared is your best bet. Confidence will reduce any Anxiety.