Kaylee went through a phase like that....she grew out of it pretty quick. No worries, I think its pretty normal....but try some of those toys that hang from the carseat handle that will keep her attention for a while.
Maybe she doesn't like how reclined the infant seat is? If she has good head control, you can put her into a rear facing convertible seat a little more upright. My son has reflux, and he screamed until I put him more upright. If you need any suggestions on new seats or any other questions, please feel free to pm me.