Short version: don't replace those calories with ANYTHING. So yes, I do think you should be eating 1200-1400 calories per day. Some of the calorie reduction should be in protein, but most of the reduction should be in fat.
Now I'm going to launch into a very simplified and stylized explanation. Other posters are correct in that metabolism is more complex. But IMO this explanation is good enough for weight loss.
Explanation: Our bodies have the ability to make hormones to burn sugar and to burn fat. CW SADs are so used to sugar that the body makes mostly sugar burn hormones and don't make many fat burning hormones. It's even worse if you're on a low-fat diet. Your body has even less reason to make fat-burning hormones. If you're a sugar burner, when you use up all your sugar, your body doesn't automatically turn to burning fat. Your body doesn't know how to burn fat, in fact your body doesn't know that it's fat. Instead of looking toward the fat, your hungry SAD body just screams out for more sugar. That's the "hunger" you're feeling. So you SAD body fills up on sugar and leaves the fat untouched.
So Step 1 in going Primal/Paleo for weight loss is to get your body to make and use those fat-burner hormones, to re-learn how to burn fat. The way to do this is to eat lots of fat and no sugar/carbs. This forces your body to learn to metabolize fat. Carb flu is part of this transition.
It sounds like you've already completed the transition in Step 1. After a month of strict Primal, you feel great, so your body is likely a fat-burner. Step 2 is to cut your fat intake. This is when Primal starts to LOOK like CICO, but not quite. Instead of calories in minus calories out, think of it as fat grams in minus fat grams out. To reword the old saying, a fat gram IS a fat gram IS a fat gram. As a fat burner, to lose weight you need to eat less fat grams than you burn. And yes it is that simple, but only after your body has ramped up the hormones to burn fat..
How many calories or fat grams do you need in a day so you can produce an energy deficit? I don't know exactly, but general consensus is that 1500-1700 is maintenance for a sedentary Primal woman. Since you have extra fat to burn, you need to take in less. This is why I advocated reducing your calories to 1200-1400 by eating less fat. It doesn't sounds like much food, but remember, those calories are fat and protein now. Once you get used to it, those 1200-1400 calories will be VERY filling.
The problem with SW CICO is that CW doesn't understand that you have to get off of carbs and turn into a fat burner FIRST. After that, THEN it turns into an energy deficit. But instead of counting calories, you count your fat grams. (this is in addition to limiting your carb grams, of course.)