Nipple shield question

So I started using nipple shields in the hospital at the advice of the lactation consultants due to baby having trouble latching due to flat nipples. Due to the difficulty, I mostly pump & bottle feed but still try to bf a few times a day (morning & night). Baby is now 4 weeks old & i am starting to suspect that when I bf w/ shield, he isn't getting as much milk bc he gets Hungry again less than an hour later. Every time i try to bf w/o the shield, he gets frustrated, latches poorly and/or is unable to latch at all. Has anyone had success w/ weaning off the shields or have any tips? Tia!