Hello Jacko.
The knack with all of this is to cut out the wrong foods then replace them with safe ones. That way you blood levels will normalise but you will still be eating enough to do stuff. Also if your blood levels have been running high then the tiredness you are getting is a common problem that many newly diagnosed people have. Your body has got use to all that sugar and is protesting that you've taken it away. The tiredness can take a while to pass but it does and your nurse is right that so long as you are controlling through diet or diet and a drug called Metformin your levels can't go too low. It's not being diabetic that causes low blood levels but powerful diabetic drugs and insulin injections. Trouble is if you give in to it then down the line you really will risk some pretty nasty stuff happening. To be honest based on what you've listed you are not eating enough and most of us (despite what our nurses say) can't tolerate porridge or most cereals.
Anyway here's what I did so I hope this helps. I was diagnosed in December last year and using the advice I found on this site I got my blood sugar levels back to normal within around a couple of months or so and I have also normalised my cholesterol levels and blood pressure as well. I have now lost over three and a half stone in weight too. My doctor is very pleased how I am getting on and has advised me to keep doing what I have been doing since it's obviously working really well. Not a cure as I still have to be very careful what I eat but I feel loads better than I did.
Diet wise its really easy. Just drastically cut down or better cut out all things with plain sugar, so biscuits, cakes, sugar in tea and coffee, pure fruit juices, non diet versions of soft drinks. Next and
REALLY IMPORTANTLY try halving starchy foods like rice, pasta, potatoes, bread, cereals and any other flour based products. Replace what's now missing with extra meat, fish, eggs, cheese and especially vegetables. Vegetables that grow above ground are best although most of us find carrots fine. Things like yoghurt are fine as is a small amount of fresh fruit. I find the ones that end in "berry" are the best. If you don't mind artificial sweeteners things like Diet Coke are fine to drink. On the starchy foods that are left swap try brown basmati rice instead of white and brown or tri-colour pasta. The bread that most recommend is actually Bergen soya bread but some do ok with wholemeal as well.
The above diet is close to one you would be one recommended to try by the Swedish Health service. It was introduced in that country last year and the American health service and several other countries health services recommend something very similar for Type 2 diabetics. In the UK the diet guidelines are now over 30 years old and are only gradually being updated. As the UK is lagging behind you have already seen what I and other forum members recommend is different to what your are told is a good diet for you follow.
Did your doctor prescribe a blood meter and strips to test your own levels. Most of us would recommend you do test. It's a bit of a post code lottery and we find the progressive surgeries are pro testing and others anti. I'll warn you the anti ones can sometimes be very vocally anti! It might be worth asking but if you find your surgery is really anti then many of us would recommend getting a meter and strips yourself. If that turns out to be the case then just ask and lots of members can help.
The reason testing is important is you should try and keep your blood sugars below 8ish two hours after eating any meal. Above the 8 value is where the dangers of complications do begin to occur according to diabetic experts. So if you can't test how will you now if what you are eating is keeping you safe? The problem is every diabetic is different so my earlier advice to halve starchy foods is just a rough guide. You may find you need to eat less than half (like me) or that you can eat more than half like others.
As you get into it all and read around the forum you may see people talking about carb counting. If you want to understand what that is just ask. It is a powerful weapon that a diabetic can use to control their condition and one that many of us use to great effect.
Good luck and keep asking questions.
Regards
Steve
PS Here's two good links about what's good to eat.
First is the lady doctor who's low carb / low GI recommendations seem to form the basis of what's recommended in Sweden
http://blogg.passagen.se/dahlqvistannika/?anchor=my_lowcarb_dietary_programe_in
Second is a good beginners guide to low carb regimes that are excellent for reducing blood sugar levels and losing weight.
http://www.dietdoctor.com/lchf
whatever it takes!