If you're engorged, you may need to pump or hand express a little before you feed her. You may be having an overwhelming let down, or being engorged could be causing a bath latch because a hard engorged breast is harder to latch onto than a soft one.
when you stick your breast in her mouth hold it like a hamburger with one hand and when she opens her mouth hurry up and stick it in there you want her to have a good grip so you want her mouth to be on your areola and hold it there until she start sucking hard.