I run my finger over top my right foot it feels like a string is being pulled or when i flex my toes back. 29/f/250 lbs/5'7" is this diabetes?

Toes: Not likely to be diabetes but you need to see your doctor to begin to understand why your feet feel as they do. If that does not find an answer a consult with a Neurologist would be in order.

It is not: Diabetes is diagnosed by measuring your glucose levels in your blood. Given your body habits, you may be at risk. Increasing your physical activity is a simple first step in lowering your diabetes risk. The tension you describe on the top of your foot while flexing and extending your toe not consistent with diabetes.