Hi hycday,
The GMAT will NOT test you on anything from the realms of Trigonometry or Calculus. Much of the math on Test Day comes from basic Arithmetic, Algebra and Geometry (think about the math you probably did at age 13-15). There are some specialty subjects (Statistics & Standard Deviation, Permutations, Combinations and Probability) and some specific Formulas that you'll probably need to learn, but you can learn the material (and train to face the various questions that can come from it).
For most Test Takers, the most complex questions are rare versions of the subjects listed above: multi-shape Geometry questions, probability questions with very specific "limitations", etc. Keep in mind that the Quant section of the GMAT is NOT just about knowing the subject matter; it's also about knowing the various tactics that you can use to answer questions quickly, it's about organization, accuracy and thoroughness (especially in DS questions) and it's about the discipline to pace yourself throughout the section.
Have you done any practice yet?
When are you thinking about taking the GMAT?
GMAT assassins aren't born, they're made,
Rich