that they found out about your condition via your medical usage, you'll have a heck of a time proving that it's the ACTUAL reason they fired you.

Trust me when I say if they let you go, whether it was truly over your status or not, they have an iron-clad alibi (shift coverage) to back them up. It will all come down to your word against theirs, so unless you are willing to go down in a likely vicious fight, you're better off to cut your losses. You don't need to waste your time and energy on such a worthless bunch anyway!

It sucks that companies can get away with that, but it's the loophole in our employment law. The same laws that are supposed to protect workers are the ones that the smart lawyers will always angle to get around.