No period and no pms

Julia
I always have pms boobs and cramps 3-4 days after ovulation, this cycle I haven't had any? No sore boobs what so ever. Although what I've experienced is some lower back discomfort, almost like pain but less sharp and more uncomfortable. I'm now 2 days late and have headaches and if I stand up too fast I'll almost faint. Anyone with similar stories?