Waking up crying

For the past couple weeks my daughter wakes up constantly and will have the saddest cry. I put her in her bed to start the night but once she wakes up I just bring her in my bed.

Every few hours (usually less) she’ll just sit up and cry. It’s been a really long time since she’s drank a full bottle at night, she just takes a sip and goes back to sleep. She usually DEPENDS on that sip to go back to sleep. I don’t understand.

I’ve tried my version of letting her cry which lasted a whole 20 min till I couldn’t take it anymore. Usually she has weird phases but this is lasting a long time to be considered a phase.

Advise is very much welcome