one step forward two steps back

Today I did 6 x 1k with 3 min rest. I have done this workout in the past with positive results. In fact I did this workout about the same time last year and had better results. Today was not my day. the first one was completed 3:13. I went through the first 200 in 36 right on. I was thinking great right on pace. As I finished I was thinking what? Number 2 was a bit better, 3:06. 3:12/3:07/3:08/3:09. I am not feeling great post workout. I have such a long way to go that things will come around. Last year at this time under similar conditions I ran 5-10 seconds faster per repeat.