Ovulation clear blue digital tests are tricking me! Please help!!!

Andrea
Im using clear blue digital tests for checking my ovulation and for the last 3-4 months it just dont show me the right answer! Im buying now like 2-3 of the ovulation blue digital boxes and trying to compare them. Guess what? They show different answer! One shows its ovulation day with a smile face on it and the other test from a different pack show negative :( so upset and dont know how to check now to be sure im ovulating on the right day. Have you had that before with digital ovulation tests?