If you have no symptoms, it's really quite unlikely you have diabetes. I'm not sure where your weight comes into it - the fact you're skinny means it's virtually impossible for you to have type 2, and if you had type 1 you'd have symptoms. I'm not sure what sort your Dad has, but regardless, the genetic link is not that strong.
Plus, if they're not looking for diabetes, it's unlikely that they'll find it... Blood tests don't automatically look for everything - they look for what they're suspicious/want to know about.