I am very sorry to learn that you are unhappy now. but i don' t think you should be unhappy.
I know that your iamily is not rich. so your parents can' t afford to buy you something of famous brands, which makes you unhappy. but they have sent you to school so that you can receive good education and have abreght future. this is not easy for your parents. so you should think about your parents. don't ask for something that is out of your parents' reach. don' t be vain-glorious.
I also thind you should put your heart into study. read more books and then you can get a lot from reading. without the famous brand competition you will become happy.
I hope i can help you out of unhappiness. wish you happy.