Commenting before reading responses....sorry if I repeat.
It's not a big deal. I was positive last time and all it meant was I got a hep lock in my hand when it was determined that I'd be staying at the hospital (there was a possibility at first that they were going to send me home). I got a dose of antibiotics that I don't even remember getting, and then DD was born. Neither of us had any ill effects, even though I didn't get the full dose of antibiotics.
The one thing I wish someone had warned me about was that being GBS+ and getting the antibiotics can increase the chances of getting thrush, which we did. It sucked.