Hi
@Nan jack and welcome to the forum.
I think they are different things. Have you had a blood test recently, that is blood taken in a syringe and sent off to a lab? If so, then the 84 mmol/mol will be an HbA1c result. Did somebody (or you) do a finger prick test on Monday and get an reading on a hand held meter? If so, that will be an instantaneous blood glucose measurement and will be in units mmol/l
It can be a bit bewildering until you get the hang of things with the numbers but if you read around the forum you will find lots of explanations - here is one.
Can someone explain the numbers system to measure blood sugar levels please?
Your numbers are consistent. With an HbA1c of 84 mmol/mol you might expect to get spot readings of blood glucose in low double figures. The important thing is that neither are desirable and you need to think about how you are going to reduce them. There are many ways of going about it and if you read around the forum you will get an idea of the principles and the routes that have been successful for members. You need to work out what will work for you.
Above all, ask us questions. There are years of lived experience of diabetes amongst members of the forum and we only too happy to share it. No question is considered silly - we have all been in the place you are now.