Uh Oh!

So my SO & I had sex on the 19th, my period was expected on the 22nd. I’ve never used this app, but i’ve always used my other one! My other app had never given me the wrong date, but according to this one i should start tomorrow. According to my old one i’m a week late. I guess i’m asking, how accurate is this app for you guys?! & What do think is going on? I have a 8 month old daughter! We do not have protected sex. & he accidentally came in me, the 19th.