Group B strep

I just got the news that I tested positive for group B strep. I’m 35w 5 days and my midwife doesn’t think I will make it much past 37 weeks before I have my daughter because my son was born at 37. And also the fact I’ve been having contractions and have been in a lot of pain. I don’t even have my next appointment til next week and by then, I will be almost 37 weeks. I don’t understand how antibiotics will do anything in that short of a time. Has anyone gone through this? Was baby okay?

Also before I get the comment, yes I do know I could still end up carrying to term but everyone thinks it’s unlikely.