[dekhn]

First, determine whether you really want to stay for the PhD program. You may have made the wrong choice, but you need to decide that for certain. You say you are worried about getting a decent job- personally I find with a PhD in quantitative stuff, the PhD gives you a small additional set of jobs you can do (mostly academic) but good employers in tech will also hire you to just code/analyze data.

Assuming you decide to leave, Prepare your resume and apply for jobs. If you have industry experience and got accepted to a PhD program you shouldn't really have a lot of trouble finding a job if you live in an area with a large pool of jobs (boston, NYC, SF, Seattle).