Feeding but then can still pump 3 oz...is baby getting hindmilk?

AilishT

My morning feed will last about 20 minutes until she's obviously finished (won't stay on, thrashes her head away when I try to put her back on).  After that, I usually pump both sides.  From the side I fed from, I can still get 3 oz after.  The other side, I usually get about 5.5 oz.  When we bottle feed her, she usually drinks about 3 oz so I know she's definitely taking in some milk but I worry that she's getting too much foremilk.  Anyone have some insight?