If i'm 4 days into having rsv as a 23yo, how can i tell if im no long contagious?

BY CDC: People infected with RSV are usually contagious for 3 to 8 days. Adults with weakened immune systems, can continue to spread the virus even after they stop showing symptoms, for as long as 4 weeks

Shedding of the virus may continue even after your symptoms subside. Avoid contact with the elderly and with younger children for two weeks and without symptoms. Wash hands frequently, rest use nasal saline after discussion with your physician.