Pregnant? I'm only 15...

Alex • I'm not rude, I'm honest 💋
My boyfriend and I had anal last week without a condom. He pulled out and came all over me including on my vagina. After that he accidentally slid back inside me for a second and back out. The day we did all that this app said it was my fertile window and 55% chance or pregnancy.  What are the chances I'm actually pregnant?