It would be best for you to see your GP with a view to having a HbA1c test. This will (after a second test to confirm) tell you one way or the other whether you have something to worry about. It is a simple blood draw and the results are back usually within about 48 hours.
Changing your lifestyle to a healthier state is always a good idea.
As to testing, if you are testing at random times it will tell you little. Honestly, see your GP.
Just wondering if anyone has ever monitored their bloods found the to be high 8-11 at various testing times only to find that the HbA1c result is that they are not diabetic. Clutching at straws here!