Can I change my status to single after filing jointly. I divorced the same year i filed married jointly. i should have filed single and didnt understand.

divorced 09-2015; however I filed married jointly thinking that's what I was supposed to do since i was married most of the year.  i tried to amend my taxes when it was brought to my attention, but they said i couldnt change it after the deadline - but i really was single...what now?