
try talking to the disability office at your school! im not diagnosed autistic nor did anything neurodivergent abt me get me my accommodations for a single room, however based on what you described having a roommate negatively impacts you and you should see what they would need to get you a single room if this is a reason for it
also if you can prove it also negatively impacts your grades, how you function daily, etc that is even better and hopefully your doctor would be willing to corroborate that! it also doesnt have to be your primary care physician, psychiatrist, or the doctor that diagnosed who diagnosed you so if you feel like one doctor you have would be better to ask for an accommodation letter ask them