In the period immediately after infection has taken place there aren't any specific symptoms. Within two to four weeks after exposure to HIV, a person might have flu-like symptoms such as fever, swollen glands, muscle aches, diarrhea, fatigue or rash. In rare instances they may occur within a few days after the exposure has taken place.
These symptoms usually go away after a week or two. Often, if they occur at all, they're so mild they're hardly noticeable, although for some people they are severe enough to warrant calling a doctor.
It's important to keep in mind these symptoms are almost identical to those of many other illnesses. That's why testing is so important. Very often people who have the symptoms are worrying unnecessarily. Only by taking the HIV test can someone reliably know their HIV status. Everything else is just guessing and HIV is too important and issue to merely guess about.