Hi and welcome from me too.
Sounds like you have made a massive effort to get your levels down so WELL DONE but I would just like to add a word of caution to keep in the back of your mind.....
udden onset of symptoms along with a VERY high HbA1c and unintentional weight loss are all red flags for Type 1 rather than Type 2. I appreciate that you have got your levels down into range by reducing your carb intake, but if you are Type 1 that may be a temporary reprieve, so do be alert to levels rising again, even with your restricted diet and exercise. It may be weeks, months or years and it may happen after an unrelated illness.
The fact that you have got your waking fasting BG down into the normal range so quickly also suggests you are Type 1 as it often takes months for normal Type 2s to bring their waking BG levels down to that level, especially from such a huge starting point. Not knocking the effort you have put in because it is obviously huge but I don't think you can clear the visceral fat from the liver and pancreas quite that quickly.
Basically Type 1 diabetes is an autoimmune condition where the immune system kills off some of your insulin producing beta cells. Often there is a trigger like a virus and it is believed that Covid has triggered it causing a significant increase in cases, but the predisposition is usually there before the trigger. In adults the attack on beta cells is sometimes quite slow and may occur in stages, which often makes it look more like Type 2 and can respond to Type 2 management in the early stages as yours has. The remaining beta cells continue to function and if you reduce your carb intake, they can manage for a while because you have reduced their workload, but will be under increased pressure because there are less of them and gradually you reach a tipping point when too many are taken out and the remainder can no longer cover even a very restricted diet and you need injected insulin. This tipping point is a dangerous time because levels can go very high as yours did at initial diagnosis and it can happen quite quickly and if you develop ketones due to a lack of insulin, you are at risk of Diabetic Ketoacidosis, which is potentially life threatening and needs urgent treatment.
For that reason, I would encourage you to arm yourself with a pot of Ketostix to check your urine for ketones when/if your BG levels return to mid teens. Being able to monitor your BG levels is important and if you see them starting to rise again then this is likely the situation and no matter how stringent your diet or how much exercise you do, you can't reverse Type 1 and it will eventually require injected insulin.
There are 2 tests for Type 1, a C-Peptide test which measures the amount of insulin you are able to produce usually after you have eaten a carb rich meal to stimulate insulin production and an antibody test to check for the antibodies which the immune system has developed to target the beta cells. GAD antibodies are the most common but there are others. These antibodies sometimes fade after an attack so in many respects it is best to have this test done early after diagnosis to help make a Type 1 diagnosis more clear as sometimes these tests can become less definitive with time and some people end up with no clear diagnosis after years of trying to manage their diabetes with oral meds and then insulin.
Just to be clear, Type 2 diabetes is metabolic usually caused by a build up a fat in the liver and pancreas and insulin resistance develops and in the early stages, the body is usually producing excess insulin to overcome insulin resistance and if it is caught early there is a good chance that it can be pushed into remission by burning that visceral fat off and kept there by lifestyle changes. It is very different to Type 1 although both cause high BG levels but with Type 2 it is usually a slow gradual process rather than the sudden symptoms and very high HbA1c you experienced. Most GPs have little understanding of Type 1 and assume you must be Type 2 because you are not a child and/or admit to a poor diet and/or are carrying a bit of extra weight. There are many of us here on the forum who were misdiagnosed as Type 2 and we have some who went years trying to get a correct diagnosis and at least one member who still hasn't got a clear diagnosis 15 years after initial diagnosis and has been on insulin most of that time. You might wonder what difference it makes, but sadly there is a 2 tier support system within the NHS. Type 1 diabetics get much better support and access to better technology. Type 2s even those on identical treatment systems with insulin are not routinely given educational courses and technology to support them. It is wrong but it is the case. It is also often apparent in the approach of health care workers and Type 1s quite often get a more sympathetic approach than Type 2s which can sometimes be made to feel like they aren't trying hard enough and are at fault. I think the tide is slowly changing but we get many people here on the forum who experience this.
Anyway, just really wanted to explain all that because there are lots of warning bells in your story which really suggest you are Type 1 and if so, sooner or later things could deteriorate fast when you are not on insulin, particularly if you become unwell, so it is worth mentioning it to your Dr now just to plant the seeds of doubt, so that they give it some thought and keep it in your own mind and ask for some Ketostix so that you can monitor ketones if levels suddenly rise into the mid teens again. It is always the way that these things happen at inconvenient times like weekends and bank holidays and whilst on holiday and perhaps indulging in a few extra carbs or having been exposed to a virus on the flight out on holiday, so do keep a close eye on things and be prepared.
