Nervous...

Rachel
I have one 4yo son, and had a miscarriage last fall. I'm 5 wks now, and so scared. I've had a little spotting the last 2 days. My uterus feel sore today. Not crampy, just sore. My question is, when should I call the dr? I don't think it's a mc because it doesn't feel like it did Before, but I still don't know what to do.