Readings high no reason

If your levels are normally between 6-8 then it could just be down to illness, stress or poor insulin absorption, tbh there could be a number of reasons.

I would just monitor your levels and take correction doses where necessary, if these high readings continue then start looking at your insulin doses, starting off with your basal, once that's right you can then look at your insulin-to-carb ratio's, take a look at the following for an explanation on basal testing:

http://www.salforddiabetescare.co.uk/index2.php?nav_id=1007