My 9 wk old baby was sleeping 8-9 hrs @ night, now is waking up hungry around 2-3am @ 10/11 weeks old! how can i get her sleeping thought the nite again?

Wait until 3 months: A healthy baby who wakes up to be fed at night, can be fed if she is <3 months old, as her schedule is not stable at that age, even if she slept through the night at times previously. After 3 months of age, parents can give a feeding at 10 P.M. Or thereabouts, and expect the baby to sleep 6-7 hours (which is long enough to be considered "through the night" at age 3-4 months).