Baby’s weight gain

Any tips po para mag gain ng weight si baby? Currently 5months na po sya pero weight nya is 5.5 lang. Similac Tummicare po formula milk niya from NAN HA nag S26 kami pero same effects saknya panay suka. Dinedede naman niya Similac kaso 2oz 2oz lang minsan ayaw pa inaabot ng 4hrs interval 🥲 #firsttimemom