I'm going to tell my mom that she should not take my sister to a trip to los angeles
Is there a reason why you think your sister is not deserving of the trip?
She already treats her way better than me.
Its terrible if a sibling is treated better than you, I feel for you. You could have a valid reason for your feelings. Maybe your parents have a reason to do so, she might be weaker than you in ways. You have to look at the whole picture too.
Fuck it. They should know that I'm tired of everything already
Being resentful is not going to make matters better. Just go with the flow and act like you don't notice the favoritism. That way no one will get a reaction from you that they want.