Two of my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> apps say I'm 7 days late, glow says I should start my period today; which I haven't yet. I am so exhausted, my stomach is cramping really bad, my boobs are sore, I cannot stop eating..... but I've taken 4 pregnancy tests all resulting in bfn. Which app should I trust? Am I late? Why is tracking your period so hard!?