What a cry baby! Listen afatifa, you need to grow up. Everyone carries their own weight in the Western world. Your brother is carrying his own weight and he definitely would not appreciate free loaders. Living in the US/Canada/UK etc. aint like living in Pakistan where babies in their 30s are still leeching off their parents (abhi tu yeh bacha hai).
Buck up, get a job, and focus on your studies. If you feel that the like aint for you, go back home but I would suggest first finish your degree. It'll help when you move back to Pakistan.
Tough it out. You're 22 years old. You can handle it.