They are not separate. If self-employment income from ALL sources, is more than $400, then you'll report that income as a part of your personal tax return, on SCH C. In addition to regular taxes, you'll also pay self-employment taxes on that self-employment income only.
Even if it's less than $400, if the total of ALL income, regardless of it's source, is more than $6200, you are required to file a tax return. I'm sure your total income from all sources was in excess of $6200, because a person can not survive on less than that for a year, unless they are claimed as a dependent on someone else-s return - such as your parent's return.
