pregnant or not

ok ladys my past two pregnancys i have found out i was pregnant at 1 1/2 weeks! one living and they thought i was miscarrying because i was early and my levels was low. ok well i would probably be the same! i have 12 first response test come up positive since saturday! ( starting to show up posistive sooner) but i took a dollar one and it was negative! went to doctor and blood test said my hcg was 1! she told me to wait a few weeks because she thinks i am!! but could i be pregnant with a hcg at 1 at about 1 to 2 weeks?