In T2 again!

I had been diagnosed with T2 in 2015, my reading was 6.6, so I was advised to change my diet and exercise more to see if I could bring down my BS without any medication. After a few months I did achieve this and my BS was back to around 5 normal range! I stayed in remission for 3-4 years, however we moved house end of 2019 and Covid happened, so it’s just be this year when I had my bloods done again and I’m back in T2 only a lot higher than I was when originally diagnosed, at 8.1.
The doctor is giving me six weeks before my second round of bloods and to change lifestyle again to see if I can bring it down a little, or, if not , he will put me on some kind of medication. When I told him that I managed to bring it to a normal level before, he said that that’s not a guarantee second time round, which left me gutted. I thought with what I’ve been reading on this forum that it can be done, in fact some people have been T2 for 20 plus years and were able to go into remission!
Is he just just putting some fear into me to make me more determined to change things?
Also, in reading this forum people refer to high numbers for T2, what is the difference with the figures my doctor uses? What would 8.1 using the other numbers relate to. It is the HbA1c Test I get. If anyone can advise on both questions, I would be most grateful, Thank you.

Thank you EllieM for your information.
My diet has been poor for 3 years now, eating anything I wanted, because I didn’t really feel any effects of diabetes, only lately with dry mouth, some tingling sensation in lower legs/feet and eyes a bit blurry.
In the last 6 weeks I have reduced my carbs dramatically, mainly avoiding bread, sweet treats, pasta, chips and rice. This is just to see if there is a drop in numbers, after that I will introduce some of the above, only more moderately and not daily, so my forever more diet is a realistic lifestyle.
My next appointment date is 29 June 2022, so after those results I might have a better idea on what my bloods are doing. I have increased my exercise/walking which is helping with the weight loss too, I’ve averaged a loss of 2.5 lbs a week. So I’ve achieved the stone off that they wanted to see in the six weeks! Then several more to go!
I’m really hoping that my BS will have dropped too, because the doctor said if that doesn’t change in the six weeks with effort made by myself, he will put me on medication. I’ve never been on medication for diabetes as it was always diet controlled, so I’m a quite worried, I just let my eating and lack of exercise get out of hand.
If the results are the same I will mention the other testing you suggested, I will need to look it up as I haven’t heard of it. I’m a bit green on the whole diabetic issues.
Thank you once again.