How's it working out for you? Are you frequently hungry? Do you have enough energy and are you putting on muscle or getting skinnier?
Now I don't count calories, but I know I eat a lot more than that and I sit on my butt all day.
I'd have thought that 1800 won't be enough even on rest days, unless that's literally all you do, rest.
If you want to add muscle, Id say shoot for at least 2500/day, with 1 to 1.5 grams of protein per lb of body weight each day and just play with your carb to fat ratios. Adding more carbs from primal foods post workout on training days and maybe less carbs on off days, but you may find that you just do better at higher amounts of carbs every day, at least until you've put on some muscle.