could I be pregnant again 7 weeks after miscarriage?

I had a miscarriage at 6 weeks. My doctor tested my levels over the next 2 weeks to make sure my levels went back down to zero. 3 weeks after the miscarriage I think I had a period but my doctor also said I would bleed a little more. I used to have my period like clock work every 28 days. I should have had my period a week ago. I had cramps and symptoms of it starting but nothing showed. Could I be pregnant again so soon? My boobs are crazy sore like the first time I was pregnant. 
I found out so early last pregnancy and got attached too quickly. The loss was difficult so I'm scared to take another pregnancy test to find out if I'm pregnant again. 
Any advice is appreciated!