Confused

Is it possible to ovulate earlier than u thought and be pregnant? Ive been having this sharp pain way down low on my tummy. Its consistent but comes and goes through out the day. My last at was the 28 of sept and weve been bd everyother day and since sunday everyday. I had the same type of pain w my last pregnancy but unfortunately had a mc. Could i be pregnant even though the app is telling me i should have ovulated yesterday???? Need some insight plz!!!!