Maintaining Long Term Ketosis

A few years ago, I became vegan for a variety of reasons that had to do with climate change, animal cruelty and my own health. Almost two years ago, I doctor suggested trying a keto diet in order to address a chronic mystery illness [Atypical Facial Pain]. I had spent ten years trying everything else to address this condition, so I thought, “Sure, why not?” And, you know what, it worked. Well, I can’t prove that it worked, but I the pain level has certainly reduced dramatically. I’ll certainly take it. Also, removing all those sugars really made me feel better over-all. I felt stronger and and had more energy. Further, I lost about 25lbs which was about what I needed to lose. My keto-vegan diet is pretty tasty and well-balanced with whole, oragnic food, so it is rare for me to stray from the path. Then, I noticed that I was losing my ketosis levels. My weight would go up even though my diet and exercise had not changed. My face pain would also begin to increase. I was advised to try intermittent fasting to kick-start the ketosis. Now, for almost a year, I have been the thoroughly obnoxious sounding keto-vegan who does not eat between 7pm and 11am [although I am really trying to avoid being obnoxious or impose my personal life choices on anyone]. The fasting did the trick up to about a month ago. It has become really hard to maintain ketosis. Last week, I did a 48 hour fast to get into strong ketosis and was only able to maintain any level of ketosis for about two days before I lost it. As I type this, I am at hour 22 of a fast, and my keto level are nil. I am looking for any insight or advice. Has this happened to anyone else?