Help!!! Pregnant??? 😲

Ok I need some help y'all. So I was supposed to have my period 10 days ago. I know it could be stress but I dont feel stressful at all. I took a pregnancy test a day before yesterday and it came back positive. Then yesterday and today I took 2 new ones and those came back negative. I haven't been spotting, my period is normally on time, and something weird the last two days have been happening.... At night when I lay down and try to sleep, I feel my stomach, almost like pulsating. Like a heart... I'm so CONFUSED! HELP!!