I posted about this rather recently too.
Ds (who is now 2 - but this started around a year and a half?) would get himself so worked up he'd vomit. Almost always a temper tantrum, not fear, but he did vomit a couple of times from being upset over something different.
I was BESIDE myself upset!!!!
We just did our best to handle it very calmly, and tried to get him calmed down as quickly as possible. Clean up the vomit, give hugs and kisses, and move on.
This sounds like some REALLY intense separation anxiety though. I honestly don't know what to tell you to do to fix it!!
We just waited it out - this period didn't last too long, thank GOODNESS!!!
I hope you get some better advice!!