I would just like to echo what others have said. If you are still getting intense craving after 3 weeks on the diet then something is making you keep your sweet tooth, I’m guessing it’s the blueberries.
If you cut all sugar and sweeteners out of your diet you will start to loose cravings after 3 days after one week the craving will be gone.
Eliminating your cravings will help.
The best thing you can do is take some extra time out once a week to insure your success for the week. On Saturdays I go to the organic farmers market and stock up on veggies. When I come home I prep as much as I can. I use my food processer and chop up veggies to add to omelets and stir frys. I usually chop 3 onions for the week this makes cooking dinner go a lot faster. Sometimes I make mayonnaise or zucchini bread. I also put a huge pot of soup on once a week, so I have something in the fridge for when I’m hungry and not thinking clearly.
The only way of getting around this is to assume you will feel ravenously hungry and be unable to cook at some point soon. Take an evening and do all your prep work for the week, it makes things so much easier.