Unexpected Bleeding

Oh I'm nervous!
I have been TTC for almost a year and on Novermber 15 I experienced a miscarriage. This is our first month trying since then and felt really hopeful! 
My period is due on the 17th, but I have started bleeding today. My last period was completely normal, this bleeding is not normal for me. 
I was planning on calling my doctor tomorrow, but want to hear if anyone else has experienced this or if they have a cause.