So sorry to hear he's being a putz! It is probably hard for him to understand, you've been doing good for quite a while, and all the sudden you're having problems.
Have you ever shared the Spoon Theory with him? www.butyoudontlooksick.com. It is about a young college student, but really says a lot. Also, I think it was Catlady or SoleSinger who posted a writing a bit ago about how it is for us - look for a heading something like "You have to read this - it is just how we feel."
All I can suggest other than that is to talk honestly and without anger. He doesn't understand, can anyone truly understand a person's pain when they haven't experienced it directly? Has he ever had a bad flu? Could you gently remind him of how that was for him?
When he is being supportive, thank him, tell him how grateful you are and how loved it makes you feel. Support his supportiveness, I guess you could say.
Sending many gentle hugs your way dear, you know you have all of our support, we all understand. May your flare end quickly!