A diet suitable for a person with diabetes can be quite a complex thing, so it is a shame that you have been left with so little useful advice

Basically, what you need to bear in mind is that all carbohydrates will convert to glucose and raise your blood sugar levels. The trick is to choose the carbs or combinations that have a slow and steady effect and which therefore have least impact on your levels.
Many people achieve this by following the principles of the GI/GL diet (Glycaemic Index/Glycaemic Load). This explains how to select and combine different things so they will have a reduced impact on your blood sugar levels, whilst at the same time keeping variety and flexibility in your diet. I would recommend getting a copy of
The GL Diet for Dummies as a good introduction. Once you have grasped the principles (which, although they may sound complicated are actually pretty straightforward!) then you cna experiment and tailor your diet until you find food that you enjoy and tolerate well, and the appropriate portion sizes for you
🙂 Ideally, you would use a blood sugar meter to test how you react to different things so that you can eliminate things that have the worst effect and keep the things that you tolerate well.
Have you read
Jennifer's Advice and
Maggie Davey's letter, and got a copy of
Type 2 Diabetes: The First Year by Gretchen Becker? These will all give you a good understanding of diabetes and how to manage it well - and are certainly better informed than the 'professionals' you've encountered so far!
Good luck, and do ask any questions you may have, any time - there will always be someone here who will do their best to help
🙂