Hi tigerlily,
Yes it is confusing at first to know what you can and cannot eat. Telling someone to use a G.I. diet without explaining it is not very helpful as you have found.
I follow this eating plan but would stress that it does not work for everyone, we are all different and I'm afraid that one size does not fit all.
You need to get a good book called the G.I. Diet by Rick Gallop. Waterstones sell it where I live but if you cannot get a copy there it is for sale on Amazon. Several of the forum members who use this diet also use this book. It explains the principles behind it, how it works, how much you can eat of any given food and the amount of exercise needed. There is a reduction in the amount of carbohydrates for each meal but it is quite easy to follow.
You do not say if you have a meter to test your blood sugars. This is vital as you need to test to see how your blood sugars react to certain foods. They are reasonable to buy but the test strips are expensive. Ask your G.P. to provide one as it is impossible to monitor your progress without
Keep asking questions on the forum, we are all here to help.
Catherine.