Yes agree it's not flu, I had flu this year for the first time ever and I couldn't move, entire family came down and no one moved or ate for days.
As for your husband taking time off; of course in an ideal world that would be the answer. I have been really ill a few times in my life, recovered from surgeries and get virtigo attacks, when this happens my husband has to work, his work isn't very flexible. So I have to look after 4 kids and between 2-6, one with special needs. My father works and my mum is severely disabled, so it's just me.
I cope, please don't get me wrong, I have on number of items burst into tears at the fact I have no sick leave myself, the world still goes in and I'm forced to figure it out because there is no help for me, it sucks and I don't like it. However I do get through it.
I focus on the keeping the kids alive, I would get my husband to get fruit shoots or something similar (which the kids think is fantastic because they are banned either wise) and snack foods, Netflix gets switched on, nothing gets tired and we just cope with the bare minimum.
You do totally get my sympathy, it does suck big time, but that's part of why motherhood is so difficult. I don't think your husband should stay home, I do think if he can finish earlier or that he does some shopping is reasonable though. Hope you feel better quickly.