I'd keep your current course before introducing some other med/treatment for gas. It still sounds like he wants to eat when he wants to eat. I'd try as hard as you can to make sure he has food available to him 24/7 (or close to it anyway). The fact he howled, you fed him, and he went back to sleep said he was hungry.
P.S. Good on the 'no vomiting'!!! Let's hope it keeps up!
P.S. Good on the 'no vomiting'!!! Let's hope it keeps up!