Welcome to the MacInsiders community Amber, thanks for posting your question. I haven't heard of 'recovery' classes either, so I have no direct advice on the matter. But in situations like this, it's always best to go to the person that would have the most knowledge on the topic. And that would be, like the other members said, your guidance counselor. They will be able to see a much better 'high level picture' so-to-speak by looking at all your grades together, and how this specific class you're taking will affect everything whether you retake it or not.
In either case, it looks like you're quite dedicated to finding a solution and you'll persist and make it through. Good luck! And hope to see you at McMaster sometime in the future