Stressed up

Huh!!!
I'm really stressed up with my family problems already..
I really dont know why they cant solved it themselves as my sister is paying most of the things herself such as expenses, car loan, petroleum and sometimes a bit of household..
While i am here trying to work and pay everything my own..
I really dont believe that they cant solved their own probs...
They just know how to make me stressed up and ask me not to spend too much in unnecessary things..
But the truth is i did not did all those things and even if i did, is my own money..
They should really instead blame themselves for the current situation and not bringing my sister and i into the picture as well..
I'm not selfish or what but they really annoyed my sister and me..
In fact, they had spoilt our future and planning now..
Haih..
Now i really dont know what should i do?
Should i help them or just let them settle themselves as i've already took all my money for my future for them..
And i'm 21 this year, i cant afford any slips up anymore..