What Causes Delayed Periods And Increase In Appetite While Having Pcos?

I am 37 yrs old with a mild case of PCOS. I have been having headaches, nausea, backpain, cramping, and chills for the last couple of days. I am also a week late on my period. I haven't yet taken an hpt. I've also had a huge increase in my appetite, which doesn't help, since at the same time, I'm so nausiated, I can't eat. Any thoughts?