My home test were positive and I went to the er because i was hurting real bad and my bloodwork came back negative as well. I had missed my period and was always nauseous. I waited until i missed my next period (3 weeks later) and went back to the er and found out i was almost 7 weeks pregnant. So i was at least 4 weeks when my bloodwork was negative. I'm now 10 weeks and 2 days.