This is non medical advice just an opinion - if you still feel so bad go back to your health provider. Often it takes a long time to get over a bad viral infection, sometimes easily 6 to 8 weeks or more. It takes a super human effort to go back to work after being off. If you are not infectious but just suffering from a post viral fatigue it takes a lot of determination to get up out of bed and be there. But do it where ever you can. That said some companies get a bit stuffy if you try and go back to work when you have been signed off sick (for insurance purposes) But usually, having a hoarse voice sounds far worse than it actually is. At the start of some viral infections you could lie down and never want to move again, but your voice doesn't sound any different from any other day. That is the worst of starting to feel poorly. It is when you start to feel better you usually sound worse.
If you can, turn up and be there for a head count for a few days. You know you are existing under par. Use common sense. Any working above that is a bonus and then you can do your best and get going again. Max out on sleep, concentrate where you need to and don't over exercise until you are feeling much better.