Second miscarriage

Just found out I was pregnant with our supposed rainbow this past Saturday. I had my first miscarriage just 6 months ago. Ended up going to the hospital last night because my OB couldn’t get me in until Friday and I was having spotting. I’m 4 weeks pregnant and my hcg was only at 6 so she told me to prepare myself because it looks like this is going to be another miscarriage. I just don’t understand where I’ve gone wrong. I never ever expected two back to back like this. I’m still going in to consult with my OB on Friday so we’ll see. Just say a prayer for me please!