Earned income credit less than last year

Almost all of my info on my taxes makes sense this year except my EIC. My Gross income increased by roughly 3,000 dollars. My EIC went down about $500. Why is that? One of the questions posted a table https://apps.irs.gov/app/vita/content/globalmedia/earned_income_credit_table_1040i.pdf
However this tells me I need a number from a worksheet to really use this table. Any help would be appreciated.