Hi I'm Patricia And I Am 24 Years Old I

Hi I'm Patricia and I am 24 years old I have 3 children and I have been feeling as if I am pregnant I have took in urine test and blood test urine test comes out light positive but line went away blood test came out negative could I still be pregnant is it possible I've been having symptoms like headaches back pain I feel nauseated
and I have been urinating a lot also all I want to do is sleep I've been having cramps I have not bled my last period was July 9th