I am ttc and i noticed today that my nipples had some dry white stuff on them. does this mean they are leaking?

Yes: It sounds like galactorrhea - you may be leaking small amounts of milk that dried up. This can be a sign of too much prolactin hormone, which can affect your chances of getting pregnant. If you already have a child leaking milk is more common. See a reproductive endocrinologist (fertility specialist) to get checked out as you're trying to conceive. Best wishes.