6 wks Positive test 3x's now negative

Kara • Married 05/16/15
I first took a test last Tuesday morning and it can back positive. Because I couldn't believe it I took another test Tuesday afternoon, positive again. I tested again on last Thursday with another positive. I had been having symptoms for almost 2 weeks not but this past week the symptoms just weren't there as much as they were. Something told me to take another test this afternoon so I did and it came back negative. I've had not heavy cramps or any bleeding at all. I am 11 days past AF date. Anyone have this happen before? I have my first Dr appointment for next Friday but don't want to go in and they tell me I'm not pregnant. I will be devistated.