How can a married couple make a combine total of 140k, both claim married 0 , pay mortgage interest , lost over 30k in the stock market, and still owe money?

I can't see your tax return, but there are a few things I noticed when you posted your question.

• You made a combined total of $140K.
  • Was that all earned from one job, or was it multiple jobs.
  • You said you claimed Married "0".  Did you account for the other persons income?
  • The IRS has a progressive tax table.  
    • The more you make the higher percentage of tax you pay.
    • If you didn't indicate that your partner was working, Both tax withholdings start out with "0" withholding.
    • For a married couple the tax rate for $83,550 is 22%.
    • If one of you earned $83,550 or more, any balance plus all of your partners income is taxed at 22% or more.
  • You said that you had $30K in stock losses.  
    • The maximum deduction for Capital Losses is $3,000 per year.
    • You can also use the loss to offset any Capital gains, plus the $3,000 deduction.