1. It's Just Dinner.
It's just another meal. If you wanted, you could make Thanksgiving any day of the year. The only difference here is that it's dinner plus PRESSURE. But, pressure's just a feeling. You can feel that shitty feeling without letting it dictate your actions. You can be freaking out on the inside (and you likely will be, at some point next weekend; I certainly intend to be). But, taking it out on your plate won't make it better or worse. Treating the meal like just another meal sends the message to your freaked-out brain that you're okay. Because, you are. Even if dad's shitfaced and your brother announces he's a Men's Rights Activist — you're okay. I promise.
2. You Might Overeat.
For many reasons, you might actually leave the table stuffed. Maybe the meal goes long and you nibble out of boredom. Maybe you find yourself chewing and swallowing so fast because you're nervous/angry/fighting with your MRA brother. Maybe dinner started late and you were starving when you sat down. In any case, it's fine. It's uncomfortable, but it's not a tragedy. It's easy to dramatize the "crime" of overeating when you feel like a fat, bloated criminal, but rather than punish yourself, just ask yourself what happened. Maybe you can avoid it next time, if you'd rather not do it. But, remember: Everyone overeats on occasion. It happens. It's fine. This bloating, too, shall pass.
3. Some Foods Are Special.
Stuffing isn't one of them. You really can have stuffing any month of the year. (I'm still not over it.) But, maybe your aunt makes those insane pecan bars once a year and you just need another, and another. And, one to wrap up for later. If you find yourself eating past the point of full on those foods, remember that it's fine. I recently ate myself silly on pierogis in Krakow because they were holy-shit good, and I probably won't find myself in Krakow again any time soon. Trust me, sometimes a little overeating is a very good decision.
4. Neutralize The Jargon.
"I'm being so bad!" "This is my cheat day!" "Yams are actually a good carb." OMG, shut up, everyone, everywhere. Yams are yams, Thanksgiving is a Thursday, and you are only bad because you're bugging the crap out of me with this BS diet lingo. It's hard being the only anti-dieter at the table, seeing food where everyone else sees Points. That's why it's important to keep your own ammo in your back pocket.
5. Take Care Of You.
When you're back home for the weekend (or the whole week, holy hell), it's normal to revert back to your fussy, teenaged self. It'll happen even if you're spending the holiday at someone else's home. Whenever you step outside of your comfort zone, you're prone to be a little uncomfortable. Don't expect perfection. We all want a perfect, chill holiday with book-reading and couch-napping, but odds are good you'll have at least one moment of GET ME THE FUCK OUTTA HERE. My advice? Get the fuck outta there.