Also, read you meter instruction booklet - it should tell you the range that it will read as numbers, and state that above a certain level, it will simply read "HI".
I agree with suggestions to re-test clean hands, other hand, and if at all possible, re-test with a different meter. But, record results and tell diabetes team when possible - realistically, probably Monday, and drink sugar free drinks - I know milk in tea or coffee means a bit of sugar, but, not much, so I'd be tempted to have one, if you feel it necessary. If you have any other worrying symptoms, then contact NHS Direct or NHS 24 or out of hours GP, although some GPs have Sat morning surgeries, so if you're quick, you might be able to see one this morning. They would have a glucose meter, so could check your readings.