I am on a low carb diet for reactive hypoglycemia. i feel really wired a lot and can't relax. how much carb in grams should i have per snack ?

Depends on type: Not all carbs are created equal- some, like sugars and white bread and rice, raise blood sugar quickly, while others, like apples and carrots, raise blood sugar more slowly. Rather than limiting carbs you should limit carbs with a high glycemic index or only eat them with low glycemic index foods (it averages out). See http://www.Mendosa.Com/gilists.Htm ; http://www.Acu-cell.Com/dis-hyp.Html.