i breastfed my dear daughter even when i was having very bad flu, with temp at 39.6 degrees!
The lady doc that i saw was very pro breastfeeding and told me that i shouldn't stop bfing cos baby would get antibodies from me. She also gave me med that were safe for bfing.
and it's true cos baby was perfectly well the whole time i was burning up!
another male doc, who doesn't seem to be pro bfing, told me to express the milk so that i wouldn't pass bug to baby. I totally ignored his suggestion cos I was already so sick, where got time to express??? And anyway, baby would already have been exposed to the bug and the breast milk would pass on my antibodies to her... i didn't take the med he prescribed me cos he doesn't seem to know what he was talking about...
If you are worried, then you can try taking the med after bfing, but usually if the docs know you're bfing, the meds should be safe.
you can also go online to check if the meds are safe.