So im 5 days late. Fmu in a cup did a tesco pregnancy test - positive appeared straight away - yesterday it was a vfl on same

Brand of test. So today when i got that positive - in same cup of fmu i used a one step strip pregnancy test and it was negative. So did another one step and it was negative. Ive never been this late for my period bar when i was pregnant with my first. So confused. Are tesco tests known for false positives? Why else could i be so late?

Fed up!!