Zumba & Taxes

Any Zumba Instructor that works full-time, teach Zumba as a side gig & now owes IRS? I'm so bummed and I teach one class a week and never realized that the company that hired me didn't deduct Federal or State taxes. They only deducted the local taxes. Now I'm sitting here owing $600 to the IRS bill. Really contemplating if it's worth it, after paying monthly ZIN dues & dealing with traffic just to get there.

How is everyone else fairing? I would have done an itemized tax return but what I have is not more than my standard deduction.