Period with no PMS?

Hey so have you guys ever gotten a period completely out of the blue with no PMS? I usually have every symptom in the book and this time around it completely blindsided me. All I experienced was a big zit on my chin.

I started Vitex about a week and a half ago to try and start regulating my cycle so I’m hoping maybe that just eased the PMS, but still.... very strange. Tell me I’m not crazy!