testing.

SO Big A and i have decided that we want to try again...  month 3 we get 2 pos. blood test comes back and they say no...  no clue why i would get 2 pos tests ( 1 at home 1 at dr) and then a neg blood test... im not on any meds or diets so nothing to affect it... unless we are having a MC. but i dont know how between a 2 hour difference we can go from 25lvl to a <2 lvl. i am sooo frustrated.