Don't worry, you'll get it. I've been on a mountain bike since '91 and it feels like home. I've been on the road bike since '98 (to get faster on the mountain bike and smooth out my pedal stroke). At first it was like a wild party at a motel room but now it's feeling like a comfortable second home.
You are right, it does feel weird-at first. The steering, the position, the response, the everything! It didn't take too long to feel ok on the road bike though, so keep riding-and riding and riding and riding...

I don't know how much the s-works weighs, but my mountain bike is 22#. Still, definitely a weight difference though I think for me it was the handling and the knowledge that while I could roll over just about anything from stairs to road debris to huge potholes to storm drains to an emergency road abandon on the mountain bike those things could cause serious damage to bike and body on the road bike. I have found the dirt handling skills to be VERY helpful on the road bike so congratulate yourself on beginning with an advantage! Hey, look at Lance's cyclocross move at the tour last year. You can still do 40mph on a gravel road on skinny! (but don't, I don't know what I was thinking-oh yeah, WAHOOOO!!!!)