Sounds like it could be reflux - DD1 had silent reflux, so we had all those symptoms, except for the spit ups - she only had little ones, if she had any at all, most of her vomiting was happening inside her body.

I found medication didn't help her at all. We went down the road of getting a homeopathic remedy and that worked for us.

Also elevating one end of her cot helped heaps too.