There is a problem with the term ketosis (It is actually a deadly disease in cows, but just a metabolical safeguard in humans)
Ketosis is what most dieters get after 1-2 weeks of a healthy diet (atkins dieters get it faster). When you do not have enough sugar in your blood to sustain your brain (which eats only glucose) then your body turns fat and protein into sugar. During that you get ketone bodies in your blood and urine, which are the trash the fat to sugar reaction leaves behind.
It is normal to pee those out. Almost every dieter will get ketosis to a small degree, but the less sugar you eat the stronger the ketosis is for obvious reasons. Ketosis tires the organism and because you do not have sugar reserves in your liver anymore you might be susceptible to disease if you're skinny. Ketosis on its own is harmless and a healthy reaction to losing weight. If you have a problem it is not the ketosis itself, but perhaps fatigue that might set in from the diet.
If you are not on a diet and have ketosis it is a whole other issue though, it might be a sign of diabetes or another metabolical disease.
Imo if you feel tired or get sick just up your calories
Of course your GP is the one to ask, not me though.