You have the infected Pokemon through midnight in your party.
When a PokeRus inflicted Pokemon is in your party, and your DS clock hits 0:00 (midnight) then the Pokemon is cured of the virus (indicated by the small pink smiley next to your blue hexagon).
NOTE: PokeRus is very, very useful though, getting rid of it is not really a good idea. Compounded with the fact that it is completely harmless. See more information here.
Hope I helped!