[Note - this is not diagnostic advice or medical info as have no medical training but...] Glucose only usually spills over into urine when levels exceed 10mmol/L around 2 hours previously, depending on an individual's kidney threshold. As a way of disposing of excess blood glucose the kidneys will flush it out through urine (hence one of the symptoms of elevated blood glucose is an increased need to go to the toilet).
It would seem likely that some hours before your appointment your levels were significantly higher than your body wanted. Not sure when your appointment was, but it could well have been what you ate for breakfast, since mornings are usually the toughest time for the body to deal with carbohydrate.
I suggest you speak to your GP about what this means, and in the meantime try to reduce the amount of carbohydrate you are eating, especially in the mornings.
Brilliant news about your weight loss and improved BP 🙂