I really do not understand what happened. These used to be my strengths but now they are my weaknesses. I used to have a very good intuitive feel for both and somewhere in my months of studying I lost it

Now I want to stop relying on intuition and rely on good-old fashioned knowledge and I need some help.
1) Can any one suggest a good grammar book that I could study that would help me out with SC? Mind you I have to take the test on Feb 19 so something that I can read and learn quickly.
2) Is there anything I can do about CR? I especially have problems with the bold face questions. Has anyone else had these problems (I know some people have with SC but I haven't seen it with CR) and if so what have you done about it?
I would really appreciate some help. I have already took some time away from GMAT prep and now I'm back so it's not an issue of just stepping away, I think this is a legitamate problem. Any help with be greatly appreciated!!!