Why does my ultrasound shows nothing but home test shows positive, spotted for 4 day after a day period followed at exactly the same time for my due period time was heavy for 2 day and turn to dark brown very light bleed or spotting that does not require pad for 12 days with positive home pregnancy test and the ultrasound shows pod fluid collection only no gestation sac. Pls help. Last normal period was on 13 april 2020.