Try going out with friends on Chol Hamoed and even at night when your father goes to shul. You can read books (I always get some new stuff before Pesach at the Feldheim sale), magazines, take a nap… You don’t necessarily have to spend time with your family ALL THE TIME. You can also simply tell them that you need some space right now.
I think that the fact that you’re anticipating about the upcoming situation is creating your anxiety. Also, as I mentioned before, please don’t let it scare you! Why are you so scared of a panic attack? You know the breathing relaxation and what to tell yourself when suffering from one. Besides, has a panic attack EVER hurt you? Of course not. Why are you afraid then? Tell yourself you’ll be perfectly fine. You know precisely what to do. You never made a fool out of yourself, passed out or died. IT’S OKAY.
Hatzlacha Rabba. A chag kosher vesameach.