How do you deal with anxiety and rich family members?

My sister in law married someone who recieves money because he is Native American and gets tribe money. He is 18 she is 20. They have 2 kids, one which is the same age as my oldest.

He doesnt work. He doesnt feel he has too and doesnt feel she has to either. So they are spending money left and right. Brand new house $350k, have bought 4 brand new cars in the last year, one of which is a 2021.

My husband and I have been struggling to make it. He works, i dont at the moment due to health and breastfeeding my two month old. We cant afford a babysitter. He had a terrible motorcycle accident last year that almost left him disabled. We are barely making our payments and food.

I see all these nice things that they are buying and wasting food by buying a bunch of stuff and never eating it. They just throw it away like its nothing. Whereas I have a budget of $50 a week to feed my family 3 meals a day. We never throw away food. I stress about buying anything unnecessary like a new shirt. She buys new stuff all the time. How do I get over that jealousy and anxiety of being around her?

She always complains about money troubles like how she wants to buy this and that. And that she has to wait till their next monthly payment. They make $10k a month. The things that she can get in the next month would take me a year to save for. We make $2200 a month. Its not that we are bad with money at all, we live very frugaly and minimalist. But occasionally I would like to splurge once in a while.

I cant have conversations with her without wanting to pull my hair out. I know my husband and I actually worked for our things and there is that feeling of accomplishment in that. Its not like she also comes from a rich family either, but being the youngest she has always had everything handed to her. My husband being the oldest did not.

Im worried that my daughter is going to grow up wondering why her cousins get so much stuff and I could only spend $100 for their gifts this year.

Its probably stupid but I cant help the stress and anxiety when I am in her house or hearing stuff like that. I love his sister. Its just her financial situation. I am jealous but I hate myself because of that.