I'm spotting & this has never happened before. Advice??

Shelby • kaydence`s mommy [10.09.14]. rhylinn’s mommy [04.18.18]
Helloooo! 
I'm 24, almost 25, with a two year old. 
I got my period on October 24th and it ended the 29th. (completely normal amount of time for me.) well now, its 3 days later & I'm spotting. It's pink color with some brown & out of all my years of periods this has NEVER happened. Ever. 
Even when I got pregnant, I had my period after she was conceived and found out the following month she was on her way, lol. 
Also, I'm not ovulating, that doesnt start for another couple days.
Can someone please tell me what exactly this may be or if this has happened to them as well and what happened? Thaaanks!