Help?

Tiffany

So this is for my sister because shes confused and so am I. So last period my sister started her birth control pills and her period lasted longer then normal and she was bleeding super heavy and she went to the hospital for it they gave her hormone pills which she took but then she started bleeding agian a few days later from the pills she bled for about 5 days. Her app that she has says her period is late by 9 days and she has been having sex obviously unprotected If she thinks shes pregnant. What do you ladies think? Could it just be the pills that is making her period not come? Or was that bleeding she had from the pills another period so shes not technically late? Or is there a chance of pregnancy? This is her <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> she sent me.