My sister-in-law received a present that made me very upset.
Why did the present your sister-in-law received make you so upset?
That gift should have been for me.
You should not complain about a gift that someone else received. It is not favorable to be viewed as envious of others. Instead, you should be happy for the person that received the gift.
It's something I really wanted and it's not fair that she received it instead of me.
I'm sure you really wanted that gift, but you shouldn't be jealous of someone else because they received what you wanted. Be happy for them, your time to get a gift that you want will come soon enough.