spotting?

I went to the bathroom I had a panty liner on and I had a small spot but never got my period so then on the 3rd I go to the bathroom again and I have a very small spot still don't have my period this has never happened before. Between the 30th and today I've been getting like pinch Sensations in my uterus they come and go Star Lake on the left side of my uterus. Has this happened to anyone? My period isn't supposed to start till the 5th which is tomorrow