Fussy twins! Help

So my twins are 6 weeks and a day old today. They were born July 18 at 34 weeks. Last week I found out they both have really bad reflux due to cow milk intolerance. They fuss and scream all night. They hate sleeping flat on there backs. Everytime they have to pass gas or poop they scream as they are pain. They are now on a special formula but it could take a few weeks to start helping. On top of the fuss from reflux it turns out they already started teething at about 3 weeks old. I didn't think it was possible for them to start teething this early especially being preemies but I guess anything is possible. Now they fuss all day from teething and reflux and I don't know what I can do for them. I usually just hold them to my chest all day as it seems like the only way they will sleep and stay calm.