You need to speak to your employer to get this corrected for 2018 and going forward. Also, they need to assist you with resolving this issue for 2017.
Paying FICA and Social Security taxes is not as straight forward as your regular income taxes. If you make additional tax payments, they need to be directed at Medicare and Social Security in your name.
I've attached IRS information to assist you in getting this issue resolved with your employer:
https://www.irs.gov/compliance/criminal-investigation/employer-and-employee-responsibilities-employm...
[Edited response below: 03.03.2018 10:29 PM EST]
The IRS will process your tax return the way it is filed now. If they review and decide to make adjustments, they will send you a letter describing their adjustments. However, they may continue to process and send you a refund.
After you receive a corrected W-2, you can amend your 2017 return. The following information will assist you in amending your return:
Open this TurboTax
link and follow the instructions to add your corrected W-2 and amend your tax return.
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
You especially need
to wait until the IRS finalizes your
original return and you receive your refund or your payment is processed.
You will mail your
amended return to the IRS. They do not accept electronic amendments.
The following IRS
link is very helpful in understanding the amendment process.
https://www.irs.gov/newsroom/amending-your-tax-return-ten-tips
