Cephalexin while breastfeeding

Has anyone taken Cephalexin while breastfeeding? My son is only 2 and a half weeks old and I developed mastitis and was prescribed Cephalexin to take 4 times a day for 7 days a week. I know they say it is safe to take while breastfeeding but I just feel so bad taking any medication 😭.

Did your baby experience any side effects?