False Positive Preg Test???

I have taken 4 HPTs, and they've all been positive (although faintly). Today I went to the doctor's office to confirm, and theirs was negative. Could I have possibly had (FOUR) false positives at home, or is their test at the office just not as sensitive??  I asked for a blood test, but the receptionist said someone would have to call me back. Ugghhhh!!!  I don't know what to think. I had a chemical pregnancy that ended in January, and now I'm so upset thinking this might turn out similarly. What do I do now??