Business & farm

It sounds like you entered the 1099-K in the Personal Section

Wages & Income

Other Common Income

Income from Form 1099-K

Instead, enter it under "Self-Employment" income

You may need to delete (use the trash can) the entry for the 1099-K you already made

If you are using TurboTax desktop Home & Business, select the Business Tab first

• Next select Business Income and Expenses
• Set-up the business if needed, 
• (if you used TurboTax last year, the business details should have been brought over)
•  
• After the business is set-up, scroll down to Business Income and select START
• Select "1099-K Income" and START

If you are starting in a lower TurboTax Online Program, 

• select "Wages & Income" on the left side-bar
• Scroll down to Self-Employment
• Open that section and select START
•  
• You will again setup the business if it has not already been done
• You may be prompted to enter expenses first
• After expenses you can scroll down to Income
• Select "Form 1099-K" and CONTINUE

(if you need help deleting the 1099-K )

For TurboTax Desktop, switch to Forms (Upper right corner) 
To Delete a Form  using TurboTax Online:
Select Tax Tools on the left side-bar
Select Tools from that drop-down
Select “Delete a form” on the TOOLS CENTER screen
Select the form, schedule and/or worksheet you wish to remove