So I had sex on my most fertile day multiple times. My next period should be in 8 days but I am noticing some weird things. I have more weird headaches, I'm more fatigued than I had ever been, and this morning I woke up with unexplained rib pain. It's not a sharp pain, it's more dull and achy. I also have pain in my neck and on my right side. Has anyone experienced that so early before?