Home calendar vs apps?!any ideas?!

Home calendar says af was due last Saturday 9/9/17 making me 6 days late and apps say I was due Wednesday 9/13/17 making me 3 days late. My cycle is 28days. This is the 2nd month. Got a somewhat faint positive not sure if it was indent line or not yesterday and took another and it was negative! I don't know what to think. I still have no sign of af even coming besides sore breasts which is usually normal around af. I do however have a heightened sense of smell and my bf thinks I'm crazy and I have been guzzeling lemon juice like it's going out of style lol

Any ideas?! Any input would be greatly appreciated.