Broken frame, dude (or dudette). Sounds like one of the chainstays is broken or a dropout is coming out. It might be related to putting MTB wheels (135 mm OLD) into a road bike (130 mm OLD) frame. Stop riding that monster. I'd have trashed that thing when I broke the first bone, not to mention started some sort of dialogue with Specialized. 14 MPH is pretty pokey for having control problems- I don't get shimmy on my carbon fiber bike even at 60 MPH (don't know about faster since I've never gone faster). And Specialized knows how to design bikes well, so I don't think it's a design problem.