Unless you have just left a very lucrative job and taken a very big risk in trying to return to something similar in the same industry, I dont think you should be too worried.
Plus not much you can do about the economy, that is and always has been an unknown, but having said that, even in the worst of times there were always opportunities going around ... I'd say can your worries for a couple of years and enjoy B-school !
1) Algebra-101 2) Sequences 3) Set combinatorics 4) 3-D geometry
My GMAT story