J.M.
J.,
My suggestion is to talk with a lactation consultant. They can be wonderful. Maya may not like how you hold her when she nurses, have a poor latch, or she may not have a strong enough suck reflex. You can find a lactation consultant by following this link:
http://www.lllofmd-de-dc.org/index.shtml
If you pump and give her what you pump, it is easier to know how much she is getting and that may help relieve some fears that she is not eating. **BUT you will only increase your supply by pumping more or breasfeeding more and you will decrease your supply once you supplement with formula.**
A lactation consultant may suggest a breast shield to help with your daughter's latch/reducing gas. I encourage you to keep trying to breastfeed. I wish you strength, joy, and peace as you work through this difficulty.
J.