Is there a sleep settling clinic you could go to? a friend of mine had similar problems with her bub and she went to one and it really helped.
I have also heard of chiropractors being able to help with an unsettled baby and from what i have heard sometimes it is instant relief. Have u spoken to your MCHN she might be able to refer u to someone for sleep settling, but if you're really concerned make an appt to see you GP and they can invesitgate the silent reflux.
I hope it improves for you soon, try and remember you're probably doing everything right it just takes awhile for you both to work out what works and what doesn't. Good luck any time u want to vent thats what we're here for.