Withheld where?  Or do you mean you made estimated tax payments?

Client submitted a W-2 instead of a 1099 for my consulting work, and withheld Fed Tax, Soc Tax, and Medicare Tax.

Then it gets entered as a w2, not on Sch C.

With the associated expenses, the Schedule C shows a huge loss without the related revenue?

Then you need the client to cancel the W-2 and issue a 1099.  This is a big mess for them.  Did you have a true contractor relationship or was your relationship more like employee-employer?   The correct tax treatment depends on your relationship, which is not necessarily controlled by your wishes.  

You CAN’T put the expenses on schedule C if the job paid you on a W-2.  You need to get the employer to cancel the W-2 and issue a 1099 or you need a vigorous accountant.

You cannot take a deduction for self-employment taxes when you only paid the employee share of them.  If the client issued you a W2 and treated you as an employee you cannot take a deduction for what they paid and the half the employee pays is not deductible.

So, if you were not an employee you would have to get this all straightened out with the client who issued you the W2.  But, you can not deduct any of the FICA taxes with the way things currently are.