Hello Nune,
Sorry to hear that you have such a big obstacle in between you and your goal. I totally understand the feeling that we often have to put in extra work to achieve the same result as others.
Like I said to the other students before, getting your mental condition up is half of the exam prep. While I cannot offer any medical advice to you. I can help you with some study tips:
-Try to finish the entire 200-question exam. No matter how long it takes, 4, 5, 8 hours. Once you have completed a full exam you will give a message to your brain that this is achievable.
-If possible, find someone to sit with you while you are doing your exam. Just like finding a spotter in the gym, the person will keep you in check and motivates you to finish the entire exam.
-When you find yourself losing focus, take a break. Even a 10-sec eye break will help.
Remember, small steps lead to big goals