Fibromyalgia Support Group
You're not alone in your pain. Fibromyalgia is a condition that can be difficult to diagnose and manage. If you're trying to cope with pain throughout your body, sleep problems, general fatigue, or other common fibromyalgia symptoms, you're in the right place. The community is here for you to talk about therapies and share your challenges.
I would write this request now before you are working the second day in a row. Alternatively, you could work half a day on the second day (but let your boss know asap).
You're between a rock and a hard place I know. But you have to take care of YOU first. Let us know how it works out.
That doesn't mean they won't - just that they don't have too in some cases.