Not eating enough?

I've only started logging again in the last week, after my weight loss (exercise alone) had slowed down a bit.
Anyhow, I've been netting about 1600 calories on average. Am not particularly hungry between meals, basically just curbing my snacking. I run and cycle on alternate days, with a day off here and there for good measure.

Now for the last two or three days, in the afternoons, I've gotten chilly, cold hands and feet, and a lack of concentration.
Would that mean I need to eat more?
I am still working out my numbers, so it's entirely possible, just figured I ask for a few opinions :-)