Pregnant with strep b?

Hey Everyone! So I had my 2nd prenatal appointment today. My doctor said I tested positive for strep B. She said it it's a bacteria that I would have to take antibiotics for to protect the Baby. So she has me on Penicillin and said I will also be treated when I deliver. I was just wondering is this serious? as long as I am taking the penicillin it will be ok right? Also should I be taking probiotics with the Penicillin? Or is it ok to just take the Penicillin? Thanks!