Hi, when DS was 2 weeks old MCHN said he had oral thrush. At first I was afraid to give him anything so i went to see my gp who prescribed the same thing. Basically nilstat drops for DS and dactarin oral gel on my nipples. I was told to use the gel after feeds and I think it did the trick.
As Lucy said, taking some probiotics help too. Another option is to include garlic into your diet. Hope it clears up soon.