Aw, nakakabahala talaga yan, mama! From what I've heard from other parents, maliit na tyan with distention ay usually galing sa excess gas, either from poor latch (nag-swallow ng hangin habang nag-feed) or from milk na hindi pa fully digested dahil immature pa ang sistema niya. May nabasa din ako from families na may ganitong issue, x-rays showed gas trapped sa bowels, sometimes even meconium plugs, pero resolba lang with proper burping at time. The latch thing talaga ang common, kaya worth checking if she's latching well during feeds, at ginagawas nila is frequent burping and tummy time. That said, best pa rin na dalhin mo siya sa pedia para ma-rule out anything serious at ma-reassure ka, lalo na kung may ibang signs na namomoth ka, doctor lang talaga ang makakatulong best sa ganitong concerns. How's she feeding naman, comfortable ba?