Thanks for your query at DoctorSpring.
Fungal infection in breast are uncommon and most likely involves the overlying skin.
Fungal infection could be associated secondary to strep infection or acquired by some contamination.
Kindly attach the picture of affected site, if possible.
Streptococcus infection may take 10-14 days for complete cure and you should continue keflex.
You should consult with general surgeon and gynecologist (as you are lactating mother) simultaneously and should go for thorough check up.
You should also consult with dermatologist if skin appears to be involved.
You should also go for fungus & bacterial culture / sensitivity both of pus discharge or skin scrapping.
You should also go for complete blood count, renal function test, liver function test, blood sugar, urine routine microscopy as fungal infection are common when immune system is breached.
Although diflucan works but at times fungal infection is severe and may require higher antifungal like Amphotericin B.
Take care, Let me know if you have other queries.
Dr. Mayank Bhargava