What amount is entered on your 1040, Line 8? If it's not one of the following amounts, then you itemized:
The 2018 standard deduction is nearly double the 2017 amount:
$12,000 for Single
Add $1,600 if 65 or older
Add $1,600 if blind
$18,000 for Head of Household
Add $1,600 if 65 or older
Add $1,600 if blind
$24,000 for Married Filing Jointly or Surviving Spouses
Add $1,300 for each spouse 65 or older
Add $1,300 for each blind spouse
$12,000 for Married Filing Separately
Add $1,300 if 65 or older