[Batman.]

Wait, I thought your family had a history of mental illness, as well as some of them getting treatment for such.

Who cares if it's "weakness", according to your dad? What's the worst he'll say, "You're weak"? Then you get help to become stronger, thus where a professional would come into the picture.

Don't let your dad's views discourage you. If you feel you need help (which it seems like you do), then get it. It'd be better to be called "weak" for wanting help, than for you to hurt yourself, or worse.