It is completely normal for your refund to drop to zero. The amendment will include just the information you are changing or adding. When you're done, you will print and mail your amended return because they can't be e-filed.
When you amend your tax return, the original tax return is still processed as it was submitted.
If your amended return is showing a refund amount, this will be in addition to the amount on the original return.
Make sure you consider if you need to also amend your state tax return.
