Could I be pregnant?

My daughter is 7wo. Last Friday my husband and I had sex for the first time pp. He was to pull out but didn't in time and finished in me some. The following Friday (a week later) I was spotting some and only for a few hours. I'm thinking I could be pregnant again and the spotting was implantation bleeding. What do you ladies think? I have my 6w appt tomorrow and plan to ask my ob for a blood test to verify.