Your symptoms sound very much like type 1 and I too would be worried about diabetes ketoacidosis (DKA), given the weight loss and how high your reading was. My diabetes also started with blurred vision and weight loss (a stone in a fortnight, and I was only 8st 7 start with), and I was rushed to hospital with a sugar level of 20 and DKA.
You can if necessary buy a pot of Ketostix from online chemists or from Amazon, though if you're going to call your GP in the morning you can at least check whether they tested you for ketones! Otherwise, if you start to feel sick or get stomach pain, or your breath starts to smell of pear drops, don't wait to speak to the GP, go to A&E and tell them you think you have DKA - as others have said, that would be a medical emergency.
When you do speak to your GP bear in mind that they may not know very much about type 1 as it's very rare, so they may not realise that adults can get type 1 and may try to treat you for type 2 - that happens, do insist that you are tested for type 1 and/or referred to a hospital diabetes clinic for tests as a matter of urgency, because if you have type 1 the meds for type 2 will not help you, and you will need insulin asap. About half of new diagnoses of type 1 are in adults (I was 44 when I was diagnosed), so the idea that only children get it is completely wrong.
A lot of the things you will see on google about diabetes are also completely wrong, so it's not surprising you are finding conflicting advice - if you're looking for more info I'd stick to the Diabetes UK site, at least for now!
And do keep drinking lots of water, that will help to flush out the sugar.
Btw, if you have type 1, once you're on insulin you will be able to eat what you like, so just hang on to the Christmas chocolate for now! If it's type 2 you will have to be more careful, but small amounts of dark chocolate should be fine.
