I could be wrong but I don’t think they offer the Federal student loan without FAFSA - so if you’ve not done it, I don’t think you’d have that yet.
Anyway, if it were me, since you paid for CSS, I’d follow through - because they’re likely waiting for the remaining - IDOC at some and the FAFSA.
On the flipside, if you want to stop and withdraw, I’d reach out to the aid department - by phone if possible but if not email, and ask them to discard - and that you’re no longer interested in seeking aid. The only concern here would be if they didn’t follow through and still waited for more info from you - hence I think I’d follow through.
Up to you how you handle.
Best of luck.