My body is playing tricks on me...

So today, I went to the bathroom and had red blood on the TP... thought it was a little strange bc AF is due 1/23 and I'm rarely early. Go to change the tampon and nothing is there.... why does my body play tricks on me like that? Maybe I never noticed until ttc but I don't remember ever starting and then it stopping like that in the same day. I know it's AF bc it was bright red but still, why does me body have to tease me like this? Been trying for 9 months now... may call the OBGYN tomorrow.. so frustrating :(