I signed up SAT's in March. Is there enough time?

I did the same thing, and am unfortunately in a very similar way. I did not bother buying a complete gigantor prep book, because I find that that probably will not be helpful since I won't have time to get through that. I have been going through SAT vocab though for about a week. I have zero prep as well although my school just started offering ACT prep cles that might help. At your local bookstore they might have a short "cram session" book, for the unprepared test taker:(. I did not even know i was taking the test at all until last week! good luck. I have heard that you should not try to cram the night before, and get plenty of sleep with a good breakfast. I have also been told to relax, take a look at some practice problems online, review the basic math and english strategies, and pick 30 difficult vocab words to learn.