I have a degree in mathematics, and now I'd like to find a job that utilizes it. How screwed am I?

Math teacher.

You can be a math teacher or a math professor.

Other then that: Cashier, Greeter, etc.

Go back to school and get a teaching credential.
Edit:
Being a math teacher might not be your dream job, but:
a) its better than any other option that you currently have....right?
b) Its a JOB that pays money. Money that can buy you time until you DO find a job using your degree to its potential.

Beggers can't be choosers.

For the first 2 years or so of your degree, you studied the same kinds of things as engineers. the difference is that you spent the next 2 years studying abstract math concepts that have very limited application in real life, whereas engineering students spend the next 2 years studying practical applications of the math they learned the first 2 years.

I'm an engineer and the highest math I took was Differential equations, which is a sophomore level course for a math major. I then took Jr & Sr level engineering courses that taught how to use calculus and differential equations to solve problems like determining the stress in a structural beam or the vibration rate of a spring loaded shock absorber. I would imagine that you barely touched those types of subjects as a math major.

Anyway, to put it in terms you can understand, your opportunities might never reach zero, but they are rapidly converging on zero. I would highly suggest you look into what it would take to complete an engineering degree. You could probably do it in 2 years of full time study or 3-4 years of part time study with the credits you already have and it would open up exponentially more opportunities. If you don't want to go that way, consider getting an MBA degree.

You should be able to be accepted into a Computer Science MS program with a BS in math (and the things you study should be well suited to your math background).  You may be able to defer your student loans again when you go back to school and also take out new loans.  A thesis based master's program may be much more affordable than you think because tuition waivers are given for being a research assistant or teaching assistant.  Also, your faculty adviser may be able to pay you a stipend through the grants supporting their research. Overall, the cost is much different than getting something like an MBA or Master's in teaching because your research is useful work for the university.