ovulation confusion

Sophia

hi ladies! according to my app i had sex 2 days after ovulation ended but i dont actually know when i ovulate, the app just assumes mid cycle. then 2 days after the sex (yesterday) i had cramping all day. i know this is too early to be implantation cramps, period due in a week. does anyone think theres a possibility i still conceived? or what those cramps were caused by. has anyone conceived on cd19 of a 27-28 day cycle?