Girls, who had this? Did a pregnancy test with sensitivity of 20 mME/m…

Girls, who had this? Did a pregnancy test with sensitivity of 20 mME/mL, shows the second strip, weak but there, on both tests. Yesterday did with sensitivity of 10 mME/mL, shows one, the second not noticeable. Which should I believe more? Can't go for blood test yet, ultrasound is too early.