I don't understand your terminology.
"I made just under 4k worth of donations". People paid you for streaming? This is not donations, no matter what the platform calls it. This is taxable income to you, earned in return for working or providing a service.
"wrote in all I made for it under self employed". Did you report the $4k of income as self-employment income on a schedule C that was attached as part of your tax return (or your joint return with a spouse)? That's what you are supposed to do. If you reported your income, then the tax you owed was already calculated and included in your overall refund or tax due. Print a copy of your return and review it carefully, paying special attention to schedule C and schedule SE (which calculate your business profits and taxes, and which number then flow to your main tax return).
If you reported this income, what is your question now?
