Spotting or period

I'm TTC and had sore breasts from 4 DPO to 13 DPO and bad constipation and indigestion a few days before my period was due. It was supposed to start on the 6th. Yesterday was 13 DPO I had very light pink spotting that turned to brown. Later on it was more of a red but still very small amount. Usually it's heavy and bright red the first two days. I only had to wear a panty liner yesterday and today. I still have constipation and indigestion. I took a test today and it was negative. Could I be pregnant and just spotting or was that my period?