Is It Normal To Have Dark Brown Spotting?

I had my period this month on the 10th, it was normal lasted for 5 days. I am seeing this blood spots, dark brown in color from last friday night 2/25. This is something never happened to me before. My periods are very normal and regular. This is the first time that i have 2 in the same month. I went to vegad on 2/21 - 2/23, walked a lot. Do you think this is causing these or is it something else. Please advise