Maybe not, and I'm not a lawyer, but the way I read the 16th Amendment, if you want to drive a stake through the heart of the income tax, you had better repeal that amendment.
Amendment XVI - Income taxes authorized. Ratified 2/3/1913. Note History
The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.
You are correct but the Supreme Court also defined income - see if this sounds like your income.
"Income within the meaning of the Sixteenth Amendment and the Revenue Act, means 'gain'... and in such connection 'Gain' means profit...proceeding from property, severed from capital, however invested or employed, and coming in, received, or drawn by the taxpayer, for his separate use, benefit and disposal... Income is not a wage or compensation for any type of labor." Stapler v U.S., 21 F Supp 737 AT 739
"There is a clear distinction between 'profit' and 'wages' and compensation for labor CANNOT be regarded as profit within the meaning of the law. The word 'profit', as ordinarily used, means the gain made upon any business or investment--a different thing altogether from mere compensation for labor." Oliver v. Halstead, 86 S.E. Rep. 2d 859