Spotting

Cindy • Pregnant with baby #2!!
Thought I was on my period , because according to glow, I should be. But it's just been spotting and this will be the 3rd day or bare to no spotting. 
This has never happened before, and I'm 24. Had my first period at 14. Oh and plus my periods are always 2-3 months apart. 
Any ideas?