So - gained 20g in 4 days :(. We're always offering more than he takes, and feeding every two hours. If not gained much by Wed going to have tests done etc - which is good because he needs to be doing better, but I'm still worried. What could it be? What can I try in the meantime? Would hungry milk be better? He only takes about 45ml (sometimes up to 60ml if we're lucky) at a time. Would the hungry milk get more calories into him? I don't even know what they'll test for tbh. Poor baby.