If you have hypoglycemia, is it without a doubt that you also have diabetes?

Diabetes is a condition in which either you do not make enough insulin or your pancreas has stopped making insulin, or your body doesn't know how to use the insulin it makes.
Insulin takes sugar from the blood and brings it into the cells. Diabetes patients usually discover they have diabetes because they find a very high sugar level in their blood. This is called hyperglycemia. There are then a series of tests done to see it's a constant state of hyperglycemia, to diagnose diabetes. (One may have high blood sugar from other reasons besides Diabetes).

Hypoglycemia is when you have low blood sugar, the opposite of hyperglycemia. Thus this is not an indication of diabetes. Diabetics can get hypoglycemia by taking too much insulin or other blood-sugar lowering medication.

I do not know a web site for hypoglycemia but I can make a suggestion. Even though you are experiencing sugar lows, do not eat sugary food. If you eat food high in sugar, your insulin spikes and takes the large amount of sugar into the cells. This spike in insulin can cause hypoglycemia. It takes in too much sugar into the cells and you end up not having enough in your blood. A person with a tendency towards hypoglycemia needs to eat foods low in sugar frequently. This is the way to avoid spikes in insulin.
When I say sugar I mean anything white. White pasta, white bread or sugar itself. Replace these with whole grains, nuts and produce. There are also some tricks to lowering sugar in foods themselves for example, fat and fiber lower the "glycemic index" of a food. So something like a snickers bar is considered a lower sugar food then white bread because a snickers bar also has fat.
Getting enough rest and minimizing stress is also important in stablizing your body's sugar.