could I be Pregnant?

So according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> I was mean to get my period on Saturday 3rd it's now Wednesday. 7th and I haven't gotten my period. I also have another app that say I was meant today but it hasn't come yet? 
On the 20th my BF and I didn't have sex but he rubbed me? So I'm not too sure he's hands were dry but idk could I be pregnant? 
So people say to take vitamin c tablets to help make it come sooner.. Has anyone ever taken them? Does it work?