HCG levels at 15

I went to have my levels tested today after my miscarriage on May 7th. This was a test I missed, and they called me and asked me to come in because they still had the orders for it. The last test was done on May 18th and the levels were at 10. I had my AF June 15th and haven't received it yet this month. I took a few tests this week and they were all negative. Could this possibly mean I'm pregnant?!