Please someone I’m scared 😢

So my the last time me and my bf had intercourse was December of 2018 the day I was ovulating which by the way we used protection . This month I’ve literally been stressing out if I was pregnant or not like I’ve been having nausea and haven’t been eating so much . Then This Monday when I woke up there was blood on my underwear like a reddish pink blood , and I’ve only had my period for 4 days including Monday which by the way was a light flow , yesterday when I checked my pad I had dark brown discharge and when I took a shower and put a new pad on there was nothing at all when I woke up this morning . Today when I was just about to start work I went to the bathroom and saw a reddish pink stain , I’m assuming that spotting are like little dots on your underwear but mine was like a stain and then I start to get worried the 2nd day of my period I took a test it came out negative and I took another the morning after it also came out negative, On Monday imma take a test , but my question is if there’s was no flow yesterday why is there light blood now ??? Could it be emotional anxiety stress ? The picture of the stain today is below

(It wasn’t this color before )