It is easy to say we would work hard if we liked something better or if we had this or that set up but we cannot really imagine the future, how it is actually going to turn out. I would certainly stick out your college courses, working as hard as you can on them, until you have something else in place to replace them.

No job is all fun and for writing you have to be especially self-starting and if you cannot figure out how to work hard where you are now, come up with a plan on transitioning to something else, you may get stuck somewhere you have an even harder time transitioning from.

Pretend you have been assigned to write about you, your life, your problems, your current subject in school and you have to learn all about it. Start keeping a journal on that "project"/book, and keep a track of the CVs you are sending out, what responses you are getting, why you are sending to those particular jobs (how are they any better than your school work?) how you intend to save/spend the money to support yourself (if your parents are paying for school and would like you to be in school, it would not be very polite to ask them to support you when you are doing your own thing that may or may not give a result?).

Generally when we graduate from school, we get a job and go out on our own, start our own life and support ourselves. If you want to have someone else support you, you might want to make a plan and contract to discuss with them; pay them for your upkeep or promise when you are another year along (since you are in your 3rd year, of four?) you will pay them X or move out, etc. If your parents are contributing to your schooling, maybe sell them on your plan for working on English/writing and have them continue to contribute to your version of school, explaining where exactly that will get you and benefit them for their investment.

I would go talk to real people working as you wish to work and get some feel for the lifestyle and how it happens. Writing has an apprenticeship/learning period just like any other occupation, one doesn't suddenly write a best-selling book without having been working for 10+years at writing. Working full-time to support yourself eats away time and energy for writing (been there, tried that) but you cannot expect other people to support you, that's not how life works.

If your uni work will give you a degree that has a high possibility of giving you a job, I would work on that, whether I liked it or not, make a 5-year plan and do my writing on my own time, make sure I am committed and realize how difficult writing is and have some success, have been to classes and conferences and published an article/story or two, etc. before I decided to pursue it full-time.

In the 1990's when I was working full-time I took a great many writing courses and worked extremely hard on my writing but did not write my novel until I finished my second degree and was a couple years into retirement and, allegedly, able to write full-time if I wanted. I got excellent training in writing, a second degree to help me in 2007 and now I have been working on a project 24/7 for over 3 years, spending over $1,000 a month on my research but still am having trouble starting the book I really want to write.

Do some writing first. Make a good plan and work at it no matter how hard but do not start by letting go of everything else. You can let go of this vine, after you have grabbed hold of the next and are moving forward through the jungle.