it definately could be a growth spurt. there really is no set 'time' for them. My son was about 5.5 months when I noticed something similar going on. His sleeping, eating, and behavior was changing...it did pass, and I can understand your frustration, because the waiting is killer. Just hang in there! I do agree, if you have a pump, perhaps try pumping your milk if you can?
How often does she get a bottle?? Maybe some nipple confusion is going on? The flow of the bottle is so different, maybe hold off on the bottle for a few days and see what happens?? She will eat when she is hungry, just maybe follow her cues for a while, instead of offering every X hours *if that is what you do, not sure*
Sorry this is so jumbled, just trying to throw out a few ideas. I hope things calm down soon!!