Yes you have to report that as self employment income. Did you enter all your expenses? If you reported it as personal income before that was very wrong. What 1040 lines was it on in 2017 and before? Did you fill out a schedule C?
Something sounds wrong if you had a Net Profit of 11,000. The self employment tax should be about $1,500 in addition to the regular income tax on it.
Self Employment tax (Scheduled SE) is automatically generated if a person has $400 or more of net profit from self-employment on schedule C. You pay 15.3% SE tax on 92.35% of your Net Profit greater than $400. The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire. You do get to take off the 50% ER portion of the SE tax as an adjustment on 1040 Schedule 1 line 27. The SE tax is already included in your tax due or reduced your refund. It is on the 1040 Schedule 4 line 57 which goes to 1040 line 14. The SE tax is in addition to your regular income tax on the net profit.
