Art is a tough way to make a living. The few artists that I have known generally made a meager living some other way and sold a few paintings here and there, or had a spouse who was very successful and still sold a few paintings here and there, or just plain went into some other career. I also would be very reluctant to spend $50,000 per semester to do this if you do not really, really want to do it.
In contrast, I think that your idea of focusing on user interface / user experience makes a lot of sense. This is at least an area where a talent in art can be valuable, when combined with other skills.The idea of using your abilities in art to help with user interface / user experience to me makes a lot of sense.
And this is a very good point.
I know some people who have been very successful, and many who have been relatively successful. As far as I know none of us have taken what might have seemed like the shortest path to get there. We all try a bit of this and a bit of that. Eventually we each find what is right for us, but this will often take a while.
I am also concerned that you are spending a lot of money to stay at a university that does not sound like a good fit for you.
There is one thing that I learned years ago, but perhaps learned it the hard way. Just because a school is famous, and highly ranked, and hard to get accepted to, and expensive, does not necessarily mean that it is a good fit for you or a good fit for me.
I am assuming that you are already enrolled for the current semester. I would be tempted to finish out this semester as strong as you can. If I am remembering properly you are taking an introductory course in software engineering / computer programming. I would try to do as well as you can in this course. Keep in mind that debugging software can sometimes take time, longer than you expect, and therefore you should try to keep way ahead in your work. While you are at it you might want to think about possible schools to transfer to as possible alternatives to both CMU and NYU.
I would try to finish well for any semester that you start, but I would not be hesitant to take a semester or a year off.