Pregnant or not pregnant?????????

Ok so i had 3 home test show possitive even had the local hospital tell me i was pregnant on july 2nd how in the world is it that i start to bleed really bad and another hospital tells me my body shows no signs of being pregnant there is absolutely no way i have had 4 false possitives wtf has any one else experienced this or is it just me im so confused and disappointed and heartbroken