Period or pregnant?

So my period is usual very normal. I am not on birth control nor have I been for years. My period was due April 26th. It is always spot on the day or earlier by a day or two. I ended up getting it on April 27th.. but I was spotting brown/ brown discharge sometimes dark sometimes light . This continued for 3 days . In between there was very minimal light pink blood. Most times I wiped it would just be a light brown. I never had a full on period which I always have . I have never had something like this. What do I think of it ?