Here's some advice from the MedHelp website and our I'm Expecting app on spotting. You can find this in the app by going to the Pregnancy Diary from the home screen and selecting Vaginal Bleeding and Spotting from the Symptoms menu. Then click the menu bar in the upper left and select Symptoms Manual to see your symptoms.
http://www.medhelp.org/pregnancy-health/articles/Spotting-and-Vaginal-Bleeding-During-Pregnancy-Your-Symptoms-Manual/1980
By the way, there is nothing you did to cause it and there is nothing they can do to stop it. Just try to relax (easier said than done) and take care of you
Often times it is caused by SCH or an implantation bleed. 1 in 100 women have them and most often they resolve on their own. The body can reabsorb or you bleed out. I have a SCH and am currently 15 weeks, at my sonogram 2 weeks ago it shows the area is getting smaller so my body is absorbing it but it is indeed very scary. It is the leading cause of bleeding in the first trimester. If the bleeding gets heavy, I would call the doc and they will send you for an ultrasound to make sure baby is ok.
There's nothing that you can do to stop it, but as long as it's only spotting and not heavy bleeding and clots, try your very best not to stress. Spotting can be quite normal.