Just confused, any suggestion ????

Ana
So I suppose to get my period on 20th according to this add. But last month period was on 23rd. I still didn't get my period ..my breast is hurting like as usual before my period comes, I would say this time is little more pain m feeling.. So I decided to do my pregnancy test . Doller store pregnancy test says (+) yes and clear blue pregnancy test which is expensive says (-) now, m confused ... Any suggestion pls . ??????