Drop the guilt altogether! My understanding is that until you get keto-adapted (same thing as fat-adapted), you should eat as much as you need as long as you maintain your ratios. There's a lot of information about how calories aren't nearly as important as we have repeatedly been told, but that's really a different discussion, and I encourage you to look into it. For the next one to five weeks, eat what you feel. You'll notice vastly reduced hunger pangs and soon you'll be able to maintain practically any amount of calorie restriction you want. (TL;DR: don't worry about calories until your body has adapted to fat and fat-derived fuels)

Paraphrasing the ideas of Drs. Phinney and Volek from the book The Art and Science of Low Carbohydrate Living, there are two stages of the ketogenic diet. In the first, you restrict carbs and therefore go into ketosis. Your body begins producing ketones within a few days but is not ready to burn them efficiently. This is where the keto-flu comes in, but you sound like you may have more or less missed this. The second stage is keto-adaptation, when your body has produced the enzymes and such that are required to efficiently use fat and ketones. This can take anywhere from two weeks to two months. Be kind to yourself and you'll see there are many rewards that come from patience and sticking to it.

Source: On the diet since 11/13; many books, articles, blog and Reddit posts absorbed.
Edit: semi-colon added.

The advice to ignore calories in the beginning is spot on. I have coached a few friends who became intrigued with keto after my weight loss. Until you are fully keto-adapted I wouldn't even consider counting calories; just make sure your macros are on target. You should be eating at least a 2:1 ratio of fat to protein while holding net carbs low (<20g carbs is good for when you're starting out).

BTW - Pistachios are a less preferable nut choice when on keto. Better choices are Macadamia, Pecan, Brazil, or Almonds (in that order).

Down the road when you have keto rolling strong, but you feel like you may have hit a weight loss stall (or plateau) it will be time to consider the amount of food you are eating. I don't use counting calories as a measure of the energy in/energy out crap (that''s been debunked thoroughly), I instead use it as a tool to gauge how much I'm eating from day to day.

Besides what everyone else said, when I am getting back into ketosis and feel hunger pains, I always think back to how much water I have had that day. Usually I haven't had enough, and that is what I am feeling. Sometimes I really am hungry though! You will learn a lot about listening to your body through this way of eating. So don't sweat it.