Hi bristoluk and welcome.
Try not to worry too much as this will send your readings higher.
It is a shock to know that you may have diabetes and we can all empathise with you.
Have a good read around the boards and see what information you can gleen. People on here use various methods to control their diabetes and as we are all different in our response to certain foods it has to be trial and error to begin with.
Starchy carbohydrates are the worst offenders, bread, rice, pasta, cereals etc and you may have to reduce your portions or cut some of them out of your diet altogether.
Anything containing sugars also has to be avoided.
Come back with any questions you may have.
Hope this helps,
Catherine.