I have pre diabetes, can i use stevia or monk fruit or brown sugar instead of regular sugar?

Yes and no: It is not as much what but how much you consume. Life style changes including diet and especially exercise are the key to this "pre condition". I cannot emphasize the exercise part too much. Talk over an exercise plan with your physician -"don't overdo it!. You can lick this and prevent a lot of trouble down the road. Good luck.