I wanted to know a bit more about driving test experiences from the users here please

I took my driving test today and unfortunately I did not pass. According to the examiner, my mistake, which cost me negative result was that I was below 100 km/hr speed limit while overtaking on the high way and occupied the over taking lane for longer period.
there were of course some minor mistakes as well, but according to my instructor, who was listening to the feedback, that those minor mistakes does not affect the result and if not for the above major mistake, he would have passed me.
The examiner suggested that I am very good overall in handling the car and situations and would need a couple hours only.
After that, my instructor suggested that I take the next exam asap and the available slot was tomorrow itself.
I had an hour lesson today and have an additional lesson before the test itself.
Now I am getting a bit nervous that if taking the exam again so soon was a good idea or not. I am confident of my driving skills


Also, I am also a bit confused about the new system. I am one of the persons who enrolled to driving school while it was old system with more lessons and different system when giving feedback and the system moved to new one while i was learning and the feedback is now given in a different way.
According to my instructor, if car stops once or twice , it is a minor mistake, and you are allowed at least 3 minor mistakes.
But I honestly am confused what exactly are minor mistakes and what are major mistakes.

If anyone has some suggestions and tips, i would really appreciate!
Thank you in advance!