Hi busdriver450
What it might mean is that your meter cannot display the figure. It could also mean that your meter or its test strips might be malfunctioning, or that you had something on your hands when you tested - I had this once with lemon juice. It could also mean what it looks like - that you have high blood glucose.
Are you able to test for ketones?
I can't see from your info what type of diabetes you have, or whether you're on medication. In any event, forum rules prevent anyone from giving medical advice or diagnosing, and I don't want to get close to that here.
If you are at all concerned, in your shoes I would get a medical opinion - assuming you're in the UK I would ring 111 or your GP. You could also go to A&E, as a last resort.