I understand your anxiousness! This is my first Thanksgiving since being diagnosed as well and I'm a little terrified. We will get through tomorrow and all will be fine!
I'm going to my boyfriend's for dinner and I know there won't be much of anything that won't be cross-contaminated or filled with gluten and it's so difficult to not make it awkward. If I don't eat anything-- it's awkward, if I bring side dishes and only eat them-- it's awkward, so I'm just accepting the awkward moments and questions that will ensue! We've been dating for a couple years but we are still in college- next year I think I will bring something because I will know the family well enough!
Good luck with tomorrow! <3