Well, I slept last night without the deck, and I slept fine. No sweating, no weird stuff. So either it is actually the energy of the deck, or it is my reaction to having the deck so close to me when I sleep.
This is my very first deck, so I don't have experience with others to know "how" it reads. What I can tell you is that I feel like I'm picking it up rather quickly. Oddly, I bought the RWS deck as an afterthought. I bought Tarot of the Sidhe (which is absolutely gorgeous), and intended on learning to read with that. I had gotten RWS just to get started with, to have as a resource to learn off of. But I've grown very attached to that deck over only the week that I've had it, I actually feel fond of it. So I'm surprised that the positive associations I have with the deck would stress me out to a point of sleeping badly knowing it's near - I would expect to feel comforted by it, as I do when I'm awake.
I don't know, this is all new to me, so I guess I'll just have to figure it out through trial and error =)