I forgot to send in my IRA contribution by the due date and filed my taxes stating that I would deposit $5,000.00. What do I do now? Is an amendment in order?

Was it a Traditional IRA contribution that you deducted or a Roth IRA contribution - it makes a difference?

Traditional, so I could take the deduction.

If you deducted the Traditional IRA contribution, then yiu must amend to remove it.  That will probably result in you owing additional tax.

To amend your 2016 tax return:

You should *wait* until your return has been processed and you receive your refund or conformation that any tax due has been paid. (If you file an amended return while you first return is being processed it can cause extended delays for both returns if two returns are in the system at the same time). In addition, if the IRS makes any change on your original return, you might end up having to amend the amendment – a sticky process that can take a year or more).

-- Then you can start the amend process.

-- Amended returns can only be mailed - allow 8-12 weeks - can take up to 16 weeks (4 months) for processing.

See this TurboTax FAQ for help with amending:

https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed

You can check the status of your mailed amended return at this link but allow 3 weeks after mailing before checking.
http://www.irs.gov/Filing/Individuals/Amended-Returns-%28Form-1040-X%29/Wheres-My-Amended-Return-1

https://ttlc.intuit.com/replies/5114064

https://ttlc.intuit.com/replies/3288565