Question Concerning Period. Really Need Some Help

I was due to start my period 3-4 days ago based on a few different apps, I started having cramping 3 days ago, and I figured that my period was about to start so I put a tampon in that night. Next morning I went to change it, and only the very very tip had a little amount of pinkish brown blood. So I thought maybe it was just starting up that morning so I put a fresh tampon in, and went about my day.

Next time I changed it, it was the very same thing, only a little bit on the very very tip (about size of a finger nail amount of blood). This has been going on for the last 3 days. Does anyone have an idea on what could be going on, or experienced this before? Any help is very appreciated.