Please call your local La Leche League. They will have a professional liaison (usually a nurse or a lactation consultant who has also breastfed) who can give you the right information. Breastfeeding for as much of the first year as you can is very very important. Too often, docs will dismiss that and try to steer you to formula. The LLL leader will steer you in the right direction.
I once had a doc who told me to not breastfeed while on antibiotics. I nodded, took the prescription and went home to call the LLL liaison. She reassured me that it was no problem to to take the med and continue to nurse. I got over my infection and my baby never missed a feeding! (My kids never knew what a bottle was)