So I Went To Go Get A Hiv Test And

So I went to go get a Hiv test and it came back negative. I was really happy but then I started reading more and I might have got the test too soon. It was only a month since we first had sex. Well I asked the girl who I cheated with. "When was the last time she was with someone besides me" she told me three months so I thought perfect. That should give enough time for the antibody to show if anything is there.?She took a test it came back negative. While she took the hiv test my girlfriend went to urgent care for "flu like" symptoms, they said they think she has the flu but tested negative for two strains of it they think it's another strain. She's been feeling bad for two days. Plus My body is feeling weird as well.I'm extremely worried for her. It's my fault not hers. Is there anything else besides hiv that could have feeling like this?