Why is my Earned Income Credit SO much lower than last year? When I plug in my numbers on the IRS site the credit is significantly higher...

You are asking from TT Self-Employed.  First, EIC is calculated on your SE profit, not income.

Second, EIC is calculated two ways: (1) based on earned income (profit) and (2) based on AGI.  You then get the lesser of the two.

When using the IRS website, be sure you are looking at the correct filing status and number of dependents on the EIC table.  

I have a side business, so I file under self-employed but my husband has a w-2 every year, and nothing changed this year from last year, I don't understand why the big difference... I made sure on the IRS website that I entered those statuses correctly...