I’m getting significantly less aid than my little brother and we are both attending the same college

I don’t understand how any of this works, but i am 21 entering my third year of college but first year in my degree (i changed majors). This is the first year i have received aid. I am projected to get $750 for the year, while my little brother who is just starting college this upcoming semester is projected to get $6,700. I filled out the forms for us both so everything is the same. Is there something i’m not understanding? what can i do?