Apply for an intermission or leave of absence from your University before the census date for the second semester. This is a better move than outright cancellation of enrolment. It'll give you up to 12 months off uni without having to pay fees, yet your place in the course is kept. If you pursue something else in the meantime, it's no problem (and free) to then cancel your enrolment during the intermission. This at the very least provides something to fall back on if you can't manage to get into something else.
I went to a careers consulting company and it helped to make a much more considered decision second time around.
It's a ****house feeling to be stuck doing a course that isn't right, and very liberating to end up in something that you're passionate about and strongly driven to succeed.

