if 173 is what you were hovering around during your PTs then it was probably mental, and you made some silly mistakes because you were rushing or something. Just continue to work on stuff that you arent perfect on your PTs and you should be fine.

Illinois Champaign isnt a bad school either

Law schools still know that you took the test (to my understanding) so voiding scores isn't really a great idea. They'll understand that message loud and clear.