frustrated

4 days before my missed period I did a clear blue test and it had the faintest line! And then I did another clear blue 2 days before and it was a bfn and today my period should of started and it dint so I did a cheap one pound test turned out to be a bfn! I just don't understand my body! My boobs ache/sting! And they usually do this a week before my period along with backache.. I never had this the week before my supposed due period, they only just started hurting now about two days ago! I just want to know if anyone has been in a similar situation as me?