There are several things you've said which suggest it may be type 1 or LADA (which is basically the same as type 1, just slower to start, as Mike says),
@KMG - so if I were you I'd definitely ask your GP to do those GAD antibody and C-Peptide tests, as a matter of urgency as your HbA1c is so high - I wouldn't want to wait a month.
HbA1c of 146 would be very rare in previously undiagnosed type 2, whereas very high HbA1c is usual in untreated type 1.
Autoimmune conditions tend to go together and type 1 is an autoimmune condition.
Losing weight (without specifically trying to) is a common sign of type 1.
And yes, you could have type 1 with the only symptom (initially) being extreme exhaustion.
As you say, type 1 can be super dangerous
if not treated, it can lead to Ketoacidosis -
https://www.diabetes.org.uk/guide-to-diabetes/complications/diabetic_ketoacidosis - so it would be sensible for you to get a pot of Ketostix (you may be able to get them from local pharmacy, or otherwise can find online) and test your urine for ketones. They aren't expensive and are easy to use - you just wee on a stick and see if it changes colour (more detailed instructions are on the pot). If you do have anything other than trace ketones or if you get symptoms of Ketoacidosis please don't wait to talk to your GP or nurse, go straight to A&E.
The good news is that if you do have type 1, then once it is treated, it's manageable and you don't have to change your diet or give up your chocolate! But you need to find out, one way or another, which type you have. GPs and surgery diabetes nurses often don't know much about type 1 as it's rare and a specialist field, so your GP may have based her diagnosis of type 2 on your being an adult, not realising that about half of type 1s are diagnosed as adults.