1 kilogram per day is a lot. Do you have a very physical job or do you do a lot cardio? It’s possible that your previous measurements were overestimating the loss for whatever reason, and now they are correcting themselves. Anyways, it’s probably just a measurement problem. In reality you are losing fat at a steady pace.
Weight loss is generally a mix of water, fat, sometimes muscle. You’re probably not retaining any water at this point. To lose fat, one pound is equivalent to 3,000 calories. If you are not burning that you won’t be seeing a noticeable difference on the scale. But since you are on day 17, I wouldn’t advise strenuous exercise. Just stay the course for now, maybe don’t weigh yourself every day if it’s making you anxious. I’d be careful going much farther in this fast, as you typically shouldn’t be fasting this long unless you are under the supervision of a physician.