Over the last couple days I have noticed that my stools are darker that they used to be. They aren't black or anything (so I don't think it's dried blood) but they are a darker shade of brown then they used to be. Is this something to worry about, r am I just being a hypochondriac?

Edit-I forgot to add that when I had an upset stomach a couple days ago I had diarrhea, and it was normal colored. Only my normal stools seem to be darker brown then usual.