Before I get started here, I'd like to address all the readers with just a quick tip that poped in my head, and relates to the topic. When dieting, the scale will give you some very basic info, and it can be helpful, but don't rely on it to quantify your gains. Instead, go by the mirror, weekly progress pics, and the way your clothes fit. You can have periods in a diet where the scale doesn't move for wks, yet you are still getting leaner. This is especially true for athletes using gear. 

Ok, thanks for baring with me....It'll be impossible for me to give you an exact answer to your question, but I can try to share some of my knowledge to help you make the best decissions for yourself. The reason I don't know how to answer your question is because I dont know what you look like, don't know what kind of progress you made in a wk, don't know how your metabolism works and most importantly, I don't know what you were eating before, to get you to the point you are now. 

First, any time you clean your diet up, you will see an initial scale drop due to losing fluid. That being said, I imange you have seen some dramatic changes by eating a 2000 cal diet. I don't know how many cals you were eating before, but I can tell you that I feed about 2x the amount of food you are eating to a guy 30 lbs less than you! I'm working with a girl that is on keto. She weighs 120 lbs and is taking in about 1400 cals.  I think you probably need more food. At this point, your body has probably only been in ketosis for a short time. I have a feeling that your scale weight loss isn't due to being on a keto diet, but more so, from not getting enough food, period. How much more you need, I'm not sure, but if you are already getting 400g protein, I would start to add more healthy fats. 

If you are getting enough cals to sustain your muscle, you can eat a keto diet for months. A lot of females have to do keto for their full 16 wk prep. I would also add in a cheat meal or refeed, depending on how you look, between every wk to 2 wks. When you decide to come out of keto, don't just do it all at once. Slowly add carbs back in over a month or more.