i agree....if you've got a B so far, work hard to keep it.
Though if you do need a little comfort...i got a C first semester and a B second in Orgo. To prove to adcoms that I know orgo, i studied hard for the DATs on got a 23 on the orgo section. I have a few interviews, so a C isn't going to kill you BUT you do have to work that much harder to make up for it.