Can I go back to a course I withdrew from in 2015

I withdrew from a course last December and am on a new one. This one does not excite me one bit. Its week 4 now things are getting worse not better. I understand the stuff but its not exciting. I cant pretend its exciting me as I am constantly feeling low and appetite goes a lot and cant sleep and get physical pains everywhere so this wouldnt match 'its fine'. Can I return to my previous course in 2015 entry? I know I am going to have to finish this one 1. because my parents would be mad and 2. It would be my fourth application to UCAs and so it would be better to have completed something so they dont think I'm failing and going from course to course.