I'm not sure where you are located, but here where I am -I went to student services who then sent me on to what we have is called the Learning Center.. there I was given an advisor who would help me with anything I needed. She needed a letter from my Psychiatrist stating what difficulties I have and what would be beneficial in his own opinion for me to achieve great success in this College.

Now, I have NVLD, Cyclothymia, Borderline Personality Disorder, Features of Autism, and one more I can never remember... so my T suggested I have extra time for written exams, as well as a distraction reduced environment to write in. I got both of these - as well he suggested that I could benefit from a program that would read my textbooks to me so I got that but found I never used it. The program would also read all tests and anything else that was scanned into it to me.
At my college once you have your accommodations set up, we just advise our teachers that we have accommodations, what they are, and fill out a form prior to the test date and everything is set up for us.

I hope you can get some accommodations to help you..