Pregnant or not pregnant?

I took 2 tests, the first one was pregnant and the second was not pregnant but the blue horizontal line was very faint. I'm not sure what to think. I feel like I am pregnant, my body has definitely gone through some changes the past few weeks. My husband is deployed and I need to inform him for sure if I'm pregnant. I'm afraid I don't have enough HCG to show up on a blood test. Do doctors so ultra sounds to determine pregnancy results?