So I use two different period tracking apps, this one and another. <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I should be starting today. But my other tracker says I should have started on the 9th. I have been highly stressed over the past week with working full time and being a week before finals. I am however sexually active. Usually my periods are crazy painful, but I haven't had any of my regular symptoms... Thoughts? Am I just paranoid or?