What kind of pill is it? The progestin-only minipill or the estrogen-progestin combination pill? The former is generally okay for breastfeeding, though there is good anecdotal evidence that it can cause supply problems for some women. The latter is strongly contraindicated for use in nursing moms because it is known to cause supply problems. Whichever one you're taking, it's probably a good idea to go off of it for now, eliminating that variable from your breastfeeding situation. When you feel like you're back on track with nursing, then you can revisit using hormonal birth control.
How much milk are you getting when you pump?
In general, when a baby seems hungry after feeding, you should simply put him back on the breast, rather than getting him a bottle. Giving a bottle means that baby doesn't give your body the stimulation it needs in order to produce more milk, and it also teaches baby that fussing after feeding is rewarded with a bottle. That means he has less incentive to work hard at nursing.
How many times a day does your baby nurse? Is he on any sort of a schedule? Do you offer both breasts at every feeding?