In my state, you can be admitted to the state university with priority registration and other benefits. Have you looked into financial aid at privates? Check out Colleges that Change Lives ctcl.org. Will Purdue admit you again?
Maybe at the undergrad level don’t limit yourself to ecology? That would open up a lot of possibilities and you could still find a way to focus on it. And do internships, jobs, volunteer to gain experience.
I would find a therapist to help you with emotional situations and making more deliberate decisions with a longer range view. No judgment here- believe me I get it!