Confusing results!?! Help!!

About 3 days ago i tested with a digital way to early. (Af not due till 30th). Anyhow , it was obvioulsy negitive so i threw it aside after i saw the results. Well, i just looked at it again because i was curious how they work and was going to open it(ik not suppose to)but before, i could i saw it was positive!! . I am so confused the intructions even said after 30 min. The test would be blank but its a bfp. Has this happened to anyone else???