I am pregnant....right?

ok. so about 3 weeks ago i tested positive at a home test. my last period had been a few days before halloween. havent had one since. i took an hpt. it came positive. i took another one an hour later. i took one the next morning it turned positive instantly. then i went to a doc office had a pee test that came out positive and went to another doc and had a pee test and it said i was positive. i just had my first ultrasound. they said my urine tests say im about 7 weeks but the gestational sac says im 4 weeks, which the two weeks difference is the time of conception. she couldnt see anyrjing but the gestational sac on.the ultrasound. i havent bled or anything so i know its not a miscarriage. i am pregnant right??