Returning to work with an invisible disease

It is one thing to feel fit and healthy at home when you're managing the day according to your own schedule. But now that I'm back at the office expecting to function like normal, I'm deeply disappointed. I'm just not quite there mentally. My mind feels foggy and I'm struggling with the basics.  I´m distracted, lost and it feels like I keep forgetting simple everyday tasks. My colleagues have been informed that I am sick, so I get a lot of understanding, encouragement and patience.

​Despite the encouragement and nice messages, it's surprisingly hard to get started again. By lunchtime, my mental capacity is exhausted and my head feels filled with fog and cotton. The weirdest thing is that it feels like I´m not looking sick enough, and I´m afraid to appear lazy because I´m only a working half days. And even though physical activity is an important part of getting well and getting back to normal, I feel guilty for maling time for activities while I´m partly on sick leave. In reality, I'm actually being confronted with my own predjudices, and I'm a little ashamed of the times I've thought to myself "You don´t look sick .."