So yesterday i decided to take a cheap 88 cent pregnancy test because i hadnt started my period yet. i took the test at about 4 30 pm. it came back positive. Today i went into my doctors at about 4:15 pm. Before then i had been feeling very dehydrated all day so i was drinking a ton of water, so much so that my urine was almost clear. They did a urine pregnancy test and it came back negative.. does this happen often or should i just accept the negative and move on? if i was pregnant i would only be about 4 weeks along gestational by tomorrow. Also, sorry if im posting this in the wrong category..