Welcome to healthcare Magic!
First of all, I would say you should be watchful about such things!
Taking 2 gms in place of one would not cause much trouble, you can have a bit nausea
and 3-4 hours later you can get hypoglycemia
I would suggest you to have a good amount of meals and take a teaspoonful sugar three hours later.
No long term problem would occur.
If you have any doubts to clear please inform me in a Fresh Query / Follow up Query for further fine tuned opinion.
Wish you a great health!