Primal is not synonymous with low carb. Sadly, this type of situation is very common in someone who takes diets to the restrictive extreme. Primal doesn't have to be as restrictive as you made it, and unfortunately, this was you failing the diet rather than the diet failing you in my opinion.
You most certainly will gain all of the fat back if you go back to eating the way you did before. So many people make the mistake of crash dieting, only to go back to their old ways when the diet is "over". It's important to be flexible from the get-go in order to create long term habits rather than just short term crash diets.
I certainly have experienced feelings similar to yours. It seems that you have gotten into the mindset of one extreme or the other, and you've completely exclude the middle, which is where most people should be.
I suggest that you go back to the basics of controlling caloric intake, having a good idea of your macronutrient totals, and being flexible with your diet to prevent purging/binging and ruining the diet. I recommend that you read Lyle McDonald's book A Guide to Flexible Dieting, and I think you will be much better off with this approach.