Hi there! I am assuming your W-4 is up-to-date since you stated you have additional amounts withheld, etc. Without seeing your return and knowing more about your situation, I am going to suggest you use our W-4 tax calculator and our TaxCaster calculator. Have your most recent paystub and your last filed tax return handy and answer the questions to the best of your ability and you will get a proposed W-4 to submit to your employer and a very good idea of your tax liability and whether you will owe or get a refund. Then, take the appropriate steps based on the results. Here are the links:
https://turbotax.intuit.com/tax-tools/calculators/w4/
https://turbotax.intuit.com/tax-tools/
Hope this helps!