So my tax return was accepted, and I was scheduled to recieve a refund... it didn't come. The IRS said they adjusted my taxreturn down to zero. Did I make a mistake?

If the IRS adjusted your tax liability you will get a letter explaining the adjustment. 

For best results, do not guess.

@theo144k 

You have not provided any information that would be helpful to us -- you have not told us what income you entered, nothing about your filing status, nothing about the refund you expected---- if you would provide some details without your personal information maybe we could help.