i had severe gallstones when my ds2 was a bub, was miss diagnosed as muscle strain untill he was 6 weeks old, only found out what it was when i was rushed into emergencey as the pain was unbareable. i had to have surgery that night and due to the morphine i could not feed bub, he was at home with df, so had to go straight to formula, i had to stay in for a week and in that time couldnt realy "controll" the pain killers they gave me, but managed ok with minimal panadine fort once back home. if you are able to express 2 weeks or so worth of milk, you should be ok, not sure how long it stays in your system. i developed bad mastitis while recovering in hospital as i have alot of trouble expressing so it just continued to build.