How is it possible to get a negative HCG on urine and blood but be pregnant at 10 weeks?

Do you know for sure you’re pregnant and you’re not just assuming you’re pregnant because you’ve missed a period? If you’re counting 10 weeks after your last period because you’ve missed a period but you’ve never actually had a positive test odds are you’re not pregnant. However if you had a positive test and now at 10 weeks you are testing negative it can be indicative of an impending miscarriage, or an ectopic pregnancy. Only an OB can tell you for sure. Also if you’re using diluted urine for a test it can cause a false negative (if you’re drinking a lot of water right before in order to be able to pee)