baby don't wake up for eat

We switched soy formula 2 days ago and my baby girl was very fussy , a lot gas pain cry,  like bloody murder all yesterday. She cry for eat every 1-2 hours but she only drink 1-2 oz then fall asleep very deep, then wake up 10-30 mins later crying like crazy again and again Finally she got really very tired and fall sleep around 11pm and in untill now(8am here) she still sleeping not wake up even once.....she only had 16oz yesterday ( usually she take 30oz a day) so I'm kind of worried