My 3 month old has been really fussy during her...

My 3 month old has been really fussy during her bottle feeds (she is formula fed) for the past few weeks. It seems to have gotten alot worse over the last week though. Her behaviour is as follows: Wriggling constantly Turning her head from side to side Kicking her legs Trying to shove her hand in her mouth while feeding Does anyone know what this could be? Has anyone experienced the same thing with their bub and figured out what was causing it? We're thinking that maybe she needs a faster flowing teat??