I Am A Bit Puzzled And Not Exactly Sure What

I am a bit puzzled and not exactly sure what to think. I have consulted with an OBGYN regarding my inquiries but have left the office with more questions than answers. I am not trying to conceive, although I believe I may have conceived in late December unintentionally however after several First Response HPTs (that indicate a positive result) ( all of the HPTs were taken over a three month time period even after the "negative" blood test) , two beta bloods (that indicate a "negative" result) and irregular "periods" since January (lasting only two days with a "regular" flow that tapers off to spotting on the third day) I am a bit concerned and questioning why the tests would contradict one another.