Relax. Read up. Talk to your doctor.
I had it the first time and I have it this time too. It's not a big deal.
And as a FTM it is highly uniklely that you will have such a fast labour that you don't make it to the hospital for a round of antibiotics before the baby is born. Highly unlikely.
And if you didn't get antibiotics they would closely monitor your baby for signs of infection and then treat him/her.
It's something like 1 in 4 women have GBS and if it's not treated during labour there is a 1 in 200 chance it could pass to the baby.