Can I Be Pregnant While HPT Is Negative?

I am nervous that I am pregnant because I am having some symptoms. I haven't had my period and if I am correct then I am possibly 7 weeks and 2 days pregnant. I have taken two pregnancy tests that came out negative, yet I am concerned because I still have some signs that I could be pregnant. Could I be pregnant with two negative test results? Also is it possible to be pregnant with no hcg?