The only thing that matters is your mothers genetics. This is because its her and her genetics that can influence you to also release multiple eggs, resulting in fraternal twins. (Which are also the only twins that can run in the family) Identical twins are luck of the draw and just happen. Your symptoms don't indicate anything really - your levels also don't indicate anything. You need an ultrasound, do you have one set up?
Good luck, I hope you get the twins you want.