Did you have unemployment?

If you have filed early before the exclusion, the IRS will recalculate your return for the new 10,200 unemployment exemption for you. There is no need for taxpayers to file an amended return unless the calculations make the taxpayer newly eligible for additional federal credits and deductions not already included on the original tax return.

Just keep waiting.  The IRS is sending them out in batches over the summer.

See IRS article May 14, 2021

https://www.irs.gov/newsroom/irs-begins-correcting-tax-returns-for-unemployment-compensation-income-...

And see,

https://www.irs.gov/newsroom/irs-sending-more-than-2-point-8-million-refunds-to-those-who-already-pa...

Do you need to amend your state return?

https://ttlc.intuit.com/community/state-taxes/help/do-i-need-to-amend-my-state-return/00/2134732

If you didn't file early your unemployment compensation will be on Schedule 1 line 7.  The exclusion will be on Schedule 1 Line 8 as a negative number. The result flows to Form 1040 Line 8.

The IRS has sent the original refund + some interest.  For the rest all you can do is sit tight and wait until they get to your return in the pile up of the MILLIONS they have to recalculate.  Sadly there is no way to track it  so just be patient.

@bbag 

"According to TurboTax, I'm owed about $1600 more, how do I go about this, do I have to file an amended return?  "

A. YES.

"Can I do that within TurboTax?"

B.  YES but with difficulty.

@bbag 

If you got merely your original refund, and IRS has not done any adjustment for you yet, you should choose to wait to see if IRS sends more over the summer.

An amended return will take even longer than waiting to see what happens

It is still possible that you are due more than IRS calculates, if you become eligible for certain credits.

For those you must amend.

NOTE: you only get one 1040-X e-File in 2020.