Christmas/religious phobia! Medical answers only please.?

I've grown up in the church. My mom's a pastor and we live in the parsonage. I started re-evaluating my position on religion in middle school but went along with it up until this time last year when I had a giant meltdown (It turns out I'm bipolar II). Probably about 15% of the problem was the up coming Christmas season. Since I'm the pastor's kid (even at 21) everyone knows me and I feel like I am supposed to act the part. I know it's not true but it really doesn't seem to matter in my head. Even though I don't go to church anymore I'm still surrounded by religion. The Advent wreath was put on the dining room table today and I kinda freaked out because of it. Next week my mother will put up her collection of nativities up in the living room. All 40 of them. My parents are VERY understanding and supportive of my situation. I'm not being pushed into anything but I'm still on edge every second I'm around Christmas stuff. I used to love this season but now I dread it. How do I survive?