Iv'e just found out that everyone at my work knows i have aspergers

My manager has informed all of my coworkers, and i'm pretty sure she did it when i first started working as a coworker randomly said to me "my cousin has aspergers too", i asked "how did you know", and she said "our manager told her/everyone"... i have no problem with people knowing this but i feel i should have the right to let people know or not, i'm not even sure how she knows. is this illegal?

It makes sense though most of my coworkers act timidly/awkard around me