I am wondering what this could mean.

Last week, for 5 minutes I had a pinkish-white discharge it was there when I went to the washroom, then did not have it at all in between. I went to the washroom like 3 hours later and it was there again when I went to the washroom. I thought it was because I was going to start my period a couple of weeks early. That was last Monday, and to this date I have not started my period.

Then all of a sudden I had a brownish-red discharge, so I assumed I started my period 2 weeks early. I put a tampon in when I went to out, and no bleeding when I took it out. So this discharge only lasted like 5-6 hours.

I am still not bleeding, am not on birth control have not been on it for 6 months. I have had unprotected sex like twice in the past week, so I do not think I would be spotting already if I was pregnant? What could be the cause of this?