I had unprotected receptive anal sex two weeks later I got a lot of ars including rash, fever, headache, fatigue, joint pain. But my partner tested nagative one day before our sex. I tested with 3rd generation rapid blood test at 19 days and 35 days after expose and result were negative. I tested at eight weeks with four generation and result was negative. I wait to test again at three months. Why symptoms appear while tests were negative. Could be false negative? Let say, if my result at eight weeks is surely 100% accurate and conclusive, that could be mean i am HIV negative, therefor what cause all these symptoms?