Denied Graduation from College

Diagnosed with clinical depression in high school. Senior year of college doctor switched medication and had problems with time and arrrived late for a test. Professor wouldn't allow me to retake or makeup test, even with a doctors note explaining the switch in medication. As a result of missing this test I failed the class. This is the only class left to complete to receive a bachlor degree in Nursing. School will not let me retake test or class, and my professor and dean is aware of my disability. What can I do with out retaking two years of college at another school. I have heard of other students with disabilities that get special treatment with tests and exams. What rights do I have?