What do I do when this girl doesnt txt back on FB?

Okay, so I just got my friends number and FB. We started a slow conversation on FB some days ago and started to talk about random funny crap. The last message was sent a day ago, but have still got no reply yet (and i doubt I will). I also know shes been on FB after I sent the message cuz ,she has been posting that "public message thing". We are both good friends and have alot of things in common so I dont think that she dislike me or have a grudge against me, so I am totally shure about she isn't mad, but now I really dont know what to do.:-/ Pleeaaaseee heeeellllppp