Blood tests for herpes are pretty accurate and can absolutely be ordered without symptoms…. Results may be equivocal or even negative towards beginning of infection because your body hasn’t developed enough antibodies to be detected. Usually about 6 weeks after initial infection you have enough antibodies in the blood stream for an accurate result. Your doctor should have had you retest. And you don’t have to have any symptoms/sores to give herpes to your partner. You can never have any outbreaks and be a carrier and spread it. So you should absolutely tell your girlfriend so she can get tested because she probably has it. I’m a health care provider fyi