Negative splits after a mile

I hit the pool for the second consecutive day, today. I wanted to do some distance and work on speed, so I did a little bit of both. Afterward, I hit the weight room for some light chest and ab work. 

Warm up

300 free

Core

2,000 free

5 x 100 free on 2:00 (negative split)

4 x 50 free on 1:00 (negative split)

Cool down

200 breast

After doing the initial 2,000 yards, I went straight into speed sets. In the 100's did 1:31, 1:30, 1:29, 1:30 again and 1:27 to finish. In the 50's, I did :43, :42, :42 and :40. I know they were very short sets, but I did manage to negative split them. Next time I try negative splits, I'm going to add some more.

Total distance: 3,200 yards