Hey guys, I was working on a vector tonight and started using the ellipse tool

. Instead of coming out as a smooth edged ellipse though, it came out sorta like a polygonal shape which was causing me much grief and still is since I cannot complete the work I'm doing to my liking without this. I tried many different tricks but all came out with the same result, a polygon that wasn't smooth, a rectangle, or a diamond shape of some sort, as can be seen here.
http://prntscr.com/c0nz1Is there anyway to fix this? I've been trying for about half an hour now and have no bloody clue on how this works. Any help would be greatly appreciated.