
TL;DR: I have fatigue. Might be depression. Doing bad at work while I try to fix it. Modified workload hasn't helped. What option is best?

I used to have a lot of responsibility at my job. In December I developed pretty severe fatigue that knocked me out from doing much of anything physically. I've been working from bed because sitting up for too long renders me jello. My GP checked a bunch of stuff, I got my Vitamin D fixed, but it's still the same. I'm going the psychiatric route for now to see if it's depression.

My work has tried to help me fix my performance issues since these started happening while I try to get my mental health back in line, since that's part of it. It's hard to feel good mentally when I feel like death and can't take a shower standing up, and I'm doing really poorly at work and in relationships and everything I do. They put me back at a level of responsibility I was at when I started, so, modified workload. But, they still see my bad days are just as bad, and they want to know what else might work. 

I'm already working from home. I don't know what will "actually" work to help me do better when I feel like absolute garbage. Taking sick time makes me feel worse because it's lumped in with vacation time. Working part time might not work either, since when I'm sick I'm sick and nothing seems to help it, even rest. And I'd lose full time benefits. Another option is taking leave until I'm better, but that means no money at all coming in for a while (I'm not struggling though, it'd mean cutting a little into savings at most) and erasing all my vacation time in the process.

They like me. I can tell they think I'm valuable and want to help me. They've offered me a lot in the past to stay with them so I know. I just know they can't keep waiting if this takes much longer to fix and I might lose the job anyway. What can I do to keep this job until I'm better. I'm trying so hard.