Anything I haven't tried?
My 5 week old has an upset stomach. It happened last night too and he was only really content after he threw up at 2am. Today I have burped and burped him some more. Done a tummy massage and exercises. Warm bath, mylicon, rocking, swaddling, pacifier, windi stick. He hasn't pooped but has passed a lot of gas. He is also on Zantac.