Though I do feel a little silly, now having more information. My point, however, still stands. However, I was also told, and believe, that one should not go for something that they hate. Do something you not only love, but can use. If you can't, it is a waste of your money and time.
Well, now that I know why you want to leave IR, I can't exactly say you are throwing your life away. If it is that bad for you, then look for something else. Still, I do think some of that attitude is needed in IR. If there is not somebody calling put people on the inside, then excuses will be very quickly made. Somebody needs to sympathize with those being damaged. After all, people are more willing to work with those who agree, right? Do it well, and do it right, and you can still keep your job and morals. Just push through the boring Econ. ;P
So, you want to be a screenwriter, eh? Alright, I can see that. Still, I would not do the Film Studies just for that. Take the class, learn as much as you can about writing, and then write as many scripts as you can in your off time. Bother filmmakers, be it independent or Hollywood, and eventually somebody will take the script. Just be warned that screenwriters are almost always freelance, even in television. Indeed, I only say 'almost,' because I think some writers do manage to stay with only one company, though that is very, very rare. It's hardly a stable job, I'll say that, but can be fun and fulfilling. Have you considered teaching? The summers off would be a great time to write and send your scripts while still having a stable job to fall back onto. That and you would be one of the coolest English teachers ever, I'm sure of it.
Actually, speaking of learning as much as you can about writing, let me ask this: Have you taken any Technical Writing classes, in College or High School? I suggest that you do, even if you don't go for the degree. It helps with any writing, and is a highly sought-after skill. Definitely minor material at least, if you like it.
...OK, my curiosity is piqued. As a potential actor,* I have to know what some of your script ideas are. Even if it's not a full script, a pitch will do, I'm interested in hearing a little more.
*Yes, I know the hypocrisy in that statement. The difference is, I am not silly enough to go for an Acting major. I'm currently thinking Communications, with a strong chance of going into Education instead. All depends on what happens when I get there.