I don't understand /u/yoozenayim 's criticisms. It's fairly easy to guess your field of training-- there's a range of only two or three professions-- and you should be able to dig out from this, the same as you would a mortgage. Your Master's is probably a good investment in your field, and your plan is not too crazy, but it will not be easy.

Your prime-late LoC will accumulate interest of about $270 a month while you're in school. I don't know the terms of that loan and what you have to pay back, but you may be able to pay the interest out of your stipend. You may be able to take on more debt to live off of, but you've got a real pile of student debt there and you should live frugally.

One thing you might consider is getting registered/licensed and picking up some casual and replacement work while you're doing your Master's. That might make things liveable for a couple of years, but it would increase your workload considerably. You might even be able to do the Master's part-time.

When you're working in two years, pay the debt down aggressively. Continue to live like a student, and pay it off using 20 - 30% of your net income. It will take you five years, maybe more. If you're not willing/able to commit to some serious austerity for the next ten years, reconsider graduate school.