Not easy to answer your question
@Deka as it varies from person to person.
Some people feel ill with lower levels than yours, I was wandering around at 31mmol at the point of diagnosis and had felt nothing apart from the classic symptoms of excessive thirst and weeing.
It certainly isn't doing you any good though. If you start to feel ill, then get yourself down to A+E. In the meantime, you coud try reducing your carb intake - (unless you're already low carbing of course.)