Oh dear ***hugs***. You are NOT crazy. You have illness and injury issues! Of COURSE you're having trouble with the classwork! If I were in your shoes, I'd be talking to the appropriate people about getting extensions for both classes to give yourself time to recover, especially with the concussion.

Online courses are extremely difficult for me under the best of circumstances. I require the structure of the classroom to keep me on task.

You are not weak or crazy or any such thing. Not one bit.

I know that my institution has lots of support for students with extra issues. Please communicate with yours and see what kind of help is available.