You cannot file as head of household if your spouse lived with you for the last half of the year.
However, you can filed as married-joint and that may allow you more benefits than filing as head of household. Your tax rates may be lower and you will get the same credits such as the earned income credit child tax credit.
To change your filing status, try following these steps:
See this help.
If I filed in 2017 as Head of household and need to change it to married filed jointly, is the filing status the only thing I need to do on the amended form?
See this TurboTax FAQ for help with amending.
You can check the status of your amended return here, but allow 3 weeks after filing for it to show up.
I haven't filed the amended taxes yet, I needed help knowing if I only need to change that on the amended form so I can send it off. I don't have access to my own computer to download the software.