Hi dannyb,
Congratulations on such a good start and yet another vindication for low carbing.
Sorry about the setback, but you'll soon start to realise how complex things can be sometimes...
Which came first the high BG or high BP - your own comment that this came as something of a blow could just show how an incease in BG could push up the BP through stress.
On the other hand it could just be that something has crept into your diet unknown to you - a different brand of something with more carbs or even 'hidden' sugars.
Do you do post-prandial testing - this would help pick up the problem meal/product
I would also say that your weight loss was exceptionaly fast - maybe too fast - I'm no expert in this area but wonder as you are low carb and low fat if you've been running on ketosis up to now.
Of course it could be, as suggested, that tomorrow you'll have that sore throat, sneezes, coughing and temperature so many have been fighting recently - if so watch out for the sugar in the cough medicines!
It might be worth looking at a more stress reducing exercise regime than the treadmill (or to complement it) try adding 30 minutes walking outside with some deep breathing (slow release is recommended) I know it's cold but wrap up well and it feels great when you get back in.
Best of luck and don't worry if you never find the cause many of us have similar un-explained fluctuations.