Hm, speaking as someone who is a complete wreck one or two days a month... it depends on your symptoms and your type of work really? Here‘s some things I do so I don‘t call in sick every few weeks:
- Self care. Keep hydrated. Less caffeine (caffeine tends to make it worse for me)
- I have a few sets of office-appropriate, but super comfy clothes - anything tight or constricting is just not an option.
- Spend every minute outside work basically resting.
- Painkillers.
- Research typical remedies (some herbal teas, light exercise, balanced diet etc) and give them an honest try - some might work for you, at least a little.
Thing is, no matter what I know I will spend the day miserable (either in too much pain to walk or sleepy and befuddled from meds) - so I don‘t expect myself to give 100% at work then. It‘s just not possible. So whenever I can I plan work around those days, schedule important tasks for other times/work ahead so that I can spend that day per month basically doing the bare minimum while looking busy and trying not to fall asleep at my desk. As long as I make sure I catch up on my tasks, I don‘t feel too bad about one bad performance day anymore.
As for mood swings, I try and cut myself some slack and just keep my interactions at work to the bare minimum, or honestly retreat to the ladies‘ room for a cry once in a while. It‘s just what it is, it‘s hormones and I feel as long as I don‘t snap at people, I‘ve done a good job.