I’m sorry that you are in this situation but you had to know that Purdue would not be free.
Yes, as a citizen, you qualify for federal funding, but as you’ve discovered, the federal government won’t pay the full fees for your attendance. Pell is not much money and your parents wont be eligible for much in loans. You can always ask, but getting additional funding from a public university will be difficult.
Unfortunately, Purdue is a public school that gets its funding from the State of Indiana’s taxpayers. Neither you, nor your parents live in Indiana and pay taxes there, so where would they get the money from for your education?
They can’t afford to fund you, especially now. Their Financial Aid priority would be their own state residents.
Where else did you get in? What are your safeties?