I am going to suggest two books for you to read concerning the
use of a math major. Both are published by the Mathematical
Association of America (see http://www.maa.org for ordering
info.)
The first is "She Does Math" which presents short histories of 38
professional women who use mathematics in their career.
The second is perhaps more useful. It is "101 Careers in
Mathematics" It profiles over 101 professionals who graduated as
math majors. These folks are employed in all sorts of careers,
including but definitely not limited to teaching. I think you
will find that mathematics can be one of the most useful majors
you can follow.
Jon Scott