I started to google again and found that the CDC guidelines (and doctors on The Body) say that only a test 6 months after exposure, 5 months after PEP, is conclusive.
My fear was back and I couldn't wait the whole six months, so I went again for a test: 5 months and 2 weeks after exposure. Again negative.
It's just one week left to my final 6 months test. But this week, 3 weeks after our short episode of unprotected sex, my gf developed some strange symptoms. She had sore throat for one day, and she felt terribly tired. That tired that she almost fell asleep during work. Though it's better now, she still feels tired.
I am terribly afraid that I didn't wait long enough before having sex with my gf and that I exposed her.
Please, can anybody tell me about an official source that confirms the 4 months that Dr.HHH mentioned to be conclusive!?