There's some great advice here...but (IMHO) the most important is to distinguish between the credit card and student loan debt. $80K in student loans is totally, completely different from $80K (or $8K) in credit card debt. Essentially student loan payments become a fixed cost- you'll be paying them off for the forseeable future, but they're an investment in your life.
Credit card debt is a whole other story. If you're constantly accruing debt, you'll just dig yourself into a deeper hole. Plus, credit card debt is viewed in a different category from student loan debt by mortgage companies, landlords- basically anybody running a credit check on you.
If there's any way to get out of credit card debt before graduating, DO IT! Seriously. I'm close to paying off my credit card debt, and it was amazing to realize that I was paying nearly as much in my rent in debt payments just a few months ago. That's scary. Because even if you do get launched into a "20 something" opera career right out of school- say, a major YAP- you won't be getting paid enough to manage huge amounts of credit card debt. Sad, but true.
Willisbe is completely correct in what she says about the differences between singing and other businesses. One thing to keep in mind though- people in the outside world still view a Masters degree as impressive...I find this very bizarre, frankly, but in the world of day jobs, or other fields you may someday pursue, having a Masters is a big qualification. Even if it's in music- strange, but true. Maybe that will help your dad feel better
Anyway, good luck, and know that you are in no way alone!!