If you think you have been infected or potentially infected with HIV, IMMEDIATELY go to an emergency department and explain your situation. You can get a treatment that can stop you getting HIV! Here's more information relevant to Australians. Yes, science has come this far!

Also, if you are engaging in risky sexual behaviour like having sex without a condom, guys get some of your foreskin chopped off. It reduces your HIV risk. Women note, it doesn't reduce your risk of getting infected from an infected male.