for context, I'm an English teacher at a small private English school. The school is so small I'm the only teacher. No subs. 
I got my period last night and as always the first day is the worst. Cramps, headache, nausea, needing the loo every 5 minutes and I feel so freaking cold today, no matter what I do I just can't seem to get warm. So I cancelled my two afternoon lessons and asked the receptionist to deal with a meeting with a potential client herself (I mean, that's pretty much her job anyway...) 
But I feel so guilty for cancelling the classes! The nausea got worse as soon as I sent the text to my boss. I feel bad that I have to cancel two classes in one day especially since I had a week holiday the week before last. Maybe the students are losing too much lesson time this year. 
My classes today were from 4 to 5.30 and then 7 to 8 but I don't go home in the gap between meaning I'd have to sit at my desk with nothing comfy or warm for 1.5 hour all while feeling really crappy. 
Idk, just looking for someone to tell me its ok to take a sick day if i need it and tell the anxiety voices to shut the heck up.