Keto diet- 8.0 mmol/l on test strip?

Good morning,
I have been doing the keto diet for 4 days now and am alittle concerned about the ketone level. I’m using test strips to get a reading. Yesterday I was about 3.0, now I am 8.0 and I’ve had the Keto flu the last 4 days. Is this normal or should I seek help? 5’10 male 175lb, healthy, if this is needed.