Absence of PMS Symptoms

Now, usually, like clockwork, I have PMS symptoms from 10 days before my period, right up until AF decides to grace me with her presence. I am currently due to start in 5 days, and no PMS symptoms. At all. Seriously weirding me out. When I was pregnant last year, I was on a constant PMS trip. No clue what's going on this month. :/ Literally nothing has changed in diet, exercise habits, or even my stress level. Eek.