Based on your description, I suggested you gentlely pat it on his back until all gas out.
When my daughter is a baby, she has a lot of gas. I pat her for a long time. Sometimes, after I pat her, her daddy do it again and then my mother-in-law help us until my daughter can release gas.
If you are really worried about your baby status, I guess you'd better to call the nurse hot line or see the mother breast feeding clinic.
Once you did all and your baby still don't like milk, I guess you can let her aside until she is crying for hungry. But you'd better to observe her pee and poo and make sure she is not dehydro. Also you'd better keep pumping and make sure you have enough milk for him.