It's common enough that doctors know how to handle it, but rare enough that a lot of pregnant women don't know much about it. I know how hard it is to stay calm. I can't imagine the pain you went through, but having had a miscairrage I can relate to the paranoia that something may go wrong. I wish you best of luck with your little one!
I've tried to be stress/paranoia free for this baby but goodness it can be hard sometimes! Having a stillbirth at 37 weeks last year doesn't really let me stay calm this time. My Dr was cholestasis is "extremely rare" but it seems (from my own research) like it's a little more common than he was saying.
My friend had it and was fine, her baby was born happy and healthy no issues. I have gallbladder disease brought on by pregnancy and was paranoid that it would impact my baby or that I would be forced to deliver early. I'll be full term on thanks giving and there's no sign of early delivery in my future. Don't stress yourself too much about it. The stress is more likely to cause issues than the actual condition. Best of luck!