Haddun,
I play football/soccer three times a week and run a few times a week also. My sugar use varies depending on the time of day and more recently the weather conditions have started to become more of a factor than I remember when I was younger.
I have just used trial & error to work out how much (or sometimes how little carbs/sugar I need before exercising). Sorry I can't be more helpful, but at least you know its not just you!
Keep up the training!
