Let people know ahead of time you have narcolepsy especially if you have cataplexy attacks like I do

My university had a disability office that I would meet with. They gave me priority enrollment so I got to pick my classes before everyone else and get the times that work for me. They also would send a letter to all of my profs at the beginning of the semester explaining that I needed certain accommodations. This opened the door to have a conversation about what I needed from them and to explain things like I might fall asleep in class, etc.
Check to see if your Uni has something like this.

Sign up for the latest class times and study at night!