HIV negative and positive?

I had with my gf for 2 years with out condums.After marriage I am not having with her even though she insist. Now i got married and after having with my wife i had some HIV symptoms..like fever, nodes on neck and under arm. and near grone. And on the private part there are two pimples. I got doubt and tested ELISA and in that report it says Negative. 0.68 was the test result. Where as if greater then 0.90 then it is positive. I am worried if i may cross 0.90 as i have 0.68. Is that possible???? Please advise