I was positive for GBS and I didn't have enough time to get the full dose of antibiotics because my labor went too fast. They tested Jaedan and he was negative so they didn't give me or Jaedan anything other than what I had in labor. I think you should be fine though.. I'm sure if there was a concern about it, the Dr. would have let you know and given you something, especially if you were in the hospital for 4 days.. I think if you are concerned, you should let the Dr. know when you go for the next appointment for the baby/yourself to get some reassurance.