@Birdsongnicky
I agree with @TheShellBeach
Just cause you are related to them through marriage,
It does not mean you have to like them or want to spend time with them,
keep interactions with them to the minimum, least amount you can get away with in future,
no need to feel or put up with feeling like bit shit by your DiL or SiL .!
Just like in life, you are not allways going to even like or get on with everyone you meet , !
that's just way it is. !
Why stress tie yourself in knots worrying over something you have zero control over what's ever...
By the way them making you feel anxious, not comfortable, is obviously not good,
It is your gut reaction, your intuition, telling you that something is off, that they are not the kind of people who are right, good for you to be around with much ect.!
Take heed of this ,listen to this.!