VQ I definitely think you're doing the right thing assuming its lactose intolerance from overload.
If the LI is a result of another dietary intolerance ie dairy then I'd be minded to EBF on an elimination diet assuming you had no other kids (as its gentler on the gut) - but that would either mean pumping to keep your supply going for the next few weeks until you know what exactly the issue is or relactating - neither of which are feasible with 3 DCs.
If it does turn out to be CMPI in your situation I'd switch to nutramagen (sp?) and no BM as soon as symptoms worsen. You want to avoid lactose intolerance (which can result from untreated CMPI) if at all possible as its harder for them to grow out of.
To further confuse things.... most CMPI babies have secondary mild lactose intolerance - weak enough that BM wouldn't trigger it. So its hard to tell what has caused what.
It's so hard nailing these diet issues. For our next one I'm eliminating dairy and soy from 7.5 months preggers so when they arrive my milk will be free of it and we can hopefully avoid the pain, medication and instead focus on gradual reintroduction.