@blackraven
There's nothing selfish about looking after your own health and wellbeing first! YOU are your first responsibility!
I don't attend family gatherings either. This is because some of my family members give off an awful energy. Imagine, fearful competitiveness with a sort order of angry righteousness. At the slightest provocation (say, if you disagree with their beliefs) they throw a wall of furious attack energy at you along with horrible words and ill feelings. They can't stand any opposing opinion whatsoever. I find this immensely rude and antisocial.
They're also psychic vampires. Every time I spend any time with them I come away exhausted and feeling worse about myself than usual. So I avoid them. I'm not sorry for that. I don't spend my leisure time with toxic people, it doesn't matter to me if we share blood or not. Toxicity is toxicity.
You send over a dish of food and that is an effort in itself, if your sister in law is offended I think that's on her, not on you. Some people look for every opportunity to be offended just so they have something (or someone!) to complain about!
I admire you for sticking to your guns and not kowtowing to social pressure, frankly.
