Hi
Have a look at this link. It explains how Jardiance works
https://www.diabetes.co.uk/diabetes-medication/jardiance.html
Basically, it causes the body to expell excess glucose through the kidneys.
This means that you have to have higher than normal levels of glucose in the bloodstream so that the extra glucose can be removed by the drug.
If you don't eat carbs, then the drug will still remove glucose, but it will leave you with too little glucose and you would risk a hypo.
So basically she was telling you to eat enough carbs that you don't risk hypos.
Do you have a blood glucose meter so that you can test your blood glucose levels, and make sure you are not dropping too low (and that the Jardiance is actually keeping your blood glucose within target levels) ?