Y am I not getting back what I paid into taxes

Without being able to see your return, there is no way to answer your question.  

However, the simple answer is that based on your income and deductions, there is a tax liability on your return and the government or your state is keeping some of the tax withholding to cover that tax liability.  You get the leftover amount in the form of a refund.  

The opposite question is: why do you think you should get it back?

The income tax system is a "pay as you go" system.  The withholding from your pay is an estimate of what you will owe at tax filing  time.  Ideally, you pay nothing at tax time and get nothing back.