Please help

I was suppose to start my period yesterday but I only spotted. I’ve been wearing a panty liner since then but it’s clean. As I wiped the rest of the day, I had a very watery pink spotting/discharge. I had a little bit of cramping but nothing like I usually do, it was very minor. This morning it is very little pink discharge when I wipe.

I took a pregnancy test this morning and it was negative, but I read there could be a chance that I haven’t developed enough HCG hormone.

Have you experience this before?

What could be going on?