What is considered household income for form 8557 if I am living with a friend

Yes, you are required to include all this form of support on form 8557. According to the directions in Part IV, if family or friends are helping to support you, include that amount of support as a gift.

So my entire income is considered a gift? Do I list all of my expenses also? 

Gifts are excluded from reportable income on Form 8557.  This Healthcare.gov link  What to include as income  has information on what to include as income on your Form 8557.  However, your income may not be accepted as a gift if it is determined that the sole purpose of calling your income a gift  was to avoid reporting household income.