There is a good possibility that the IRS has not yet gotten to the return you filed. Just keep checking once a week and the status should become available in another month or two. We have seen messages from users who mailed their returns back in February and are still waiting for their tax refunds.
The only issue you have is knowing whether or not the return was received by the IRS. If you did not use a tracking service from the US Post Office then you will not have proof of receipt. With the backlog at the IRS do not consider mailing another amended tax return as it would only further delay the process.
