I think my period is late

Brianna • Wed, Sep 11

According to glow I am supposed to start my period today and for the last 5 months it has came like 5 days before the app says it will. I have been getting slight cramps here and there and I've been so tired. My body is especially tired and after a long day of school and work it's hard to walk around. I have also felt a little sick a few hours after I get up but not enough to throw up.