Do you have a rash? I had horrible, horrible itching when I was pregnant, and definitely went to itchymoms.com and freaked out. It turned out that I had PUPPP (which has a really long and gross-sounding name), and it's really uncomfortable, but not at all harmful. I'm sure if you've been diagnosed, then that's that, but just a thought. If you have a rash at all, it may be pupp instead.
As far as helping with the itching, the only thing that helped me was ice packs and Sarna lotion (you can get it at the pharmacy; it's with the medicated lotions). The ice packs were really the best. I hope that helps, and I hope that you don't have to deliver early, and as awful as it is, I hope you have PUPPP instead of cholestasis!