I think crabbed means the same thing as cramped.
The phrase stopped me cold means that the thing prevented the person from doing what he wanted to do. A serious disease might stop a person cold in the sense that it will prevent a person from working or doing other things he or she is used to doing.
A dog paddle is a type of swimming motion like that performed by dogs.
SAT stands for Scholastic Aptitude Test. It's a test given to high school students to see how well they are likely to do in college. See: http://encarta.msn.com/encnet/featur...fid=1861701427
ACT stands for American College Test. It's a standard college entrance exam.