Ladies, who has experienced a pseudo-menstruation!!!!!

I think I might be pregnant, but I'm not entirely sure. Ladies, what are your experiences with this? I've never had such a short and less intense period before. It only lasted 3 days, and now it's the fourth day with absolutely nothing left, just a tiny drop of light brown. The bleeding was completely different in color, more like bright reddish-brown. And it was also much less than how I always had it. I've taken a lot of tests, but they all came back negative.