GP finger prick test results

nOver the past month I have developed symptoms of diabetes, mainly excessive urination, thirst and fatigue. I am a reasonably healthy non-smoking 51 year old male and am not overweight. I am 181cm tall and weigh 73 kg. I started a candida diet a month ago on the advice of a nutritionist as I had been having stomach problems over the past 18 months and tests had shown there was no medical reason for the symptoms. She put the stomach issues down to a yeast imbalance so I commenced the diet that basically rules out all sugars, caffeine, alcohol, yeast, malt and processed foods.
My 'diabetes type' symptoms developed within a few days of starting the diet. I am not a great believer in coincidence and am trying to establish if the two could be linked. I went to see my GP a couple of days ago and had the finger prick test. The result was a score of 8.6. As I had eaten breakfast the GP said this was on the high side of normal and has referred me for full fasting blood tests that I will have next week.
The queries I have are:
1. could the candida diet have triggered diabetes or the symptoms?
2. Would a score of 8.6 be considered normal given that I haven't had any sugar for a month and my breakfast that morning consisted of oats and unsweetened almond milk
I appreciate that I am jumping the gun a little as I haven't had a diagnosis, but I am basically intrigued about these queries and can't find anything on the net.

Thanks for the replies. It was a long shot and I was intrigued. Also keen to know the results but have to wait another week!

Totto, my diet doesn't include bread or other grains apart from occasional home made soda bread made with spelt flour and yoghurt.,