Thanks for replying @speckofdust

In my case, it is problem with tendons (if it is what I had last year). Right now, it is so bad, that I cannot write for more than 20 minutes in one go so that is the problem as my exams are (except for one) written. Even typing on keyboard or phone is painful now so that's not a relief and since I study IT/programming, it is crucial to success. And at uni, you have too little time to use just one hand.
Concerning the first upcoming exam, there was not enough time to communicate it with the lecturer.

To give you a better view, I struggle with eating now because of the pain.

Writing this post took just 5 minutes and it got too painful. In my case, the problem is also that I don't have anything to relieve or lessen the pain and since I live alone and cannot really rely on anyone, so I have to take care of everything myself.