Positive then Negative

I posted this a few days ago but I’m posting again as an updated version and to see if I can get some more input. So I took a PT on Thursday and it was faint but definitely positive. I then chugged some water and took another because I was freaking out and it was negative. Then later took another and it was another super faint line. I then retested yesterday morning and it was negative. Tuesday was when my period was supposed to start and I thought it had but it wasn’t much and it was mostly brown. I have spotted off and on since then. Mostly just all brown blood. I have been feeling really nauseous and was bloated for a few days and was pretty gassy with the bloating. I have also been feeling fatigued. Can someone give me some opinions on this or if you’ve had the same thing happen? I’m posting the first positive I got on Thursday too.