My DD has not pooed in 4 days -this is a long time for her. I know lots of bubs don't go regularly but she goes everyday - sometimes twice. The most she has gone without going is one whole day. The only thing she eats/drinks is breastmilk and in last week or so she's had "licks"/"tastes" of custard - not enough to call eating though! Could this be a problem? She doesn't seem to be in pain.