you can look on www.hivtest.org and find a local place that does a rapid test. They give results in like 30 minutes or less.
1) Call your doctor's office, and see if they can order the blood test without your even seeing the doctor.
2) Go to your local public health department. They do the tests for free, but they often take a couple of weeks to come back.
3) Do a search on the Internet for various non-profit groups (gay and lesbian community organizations, Volunteers of America, HIV/AIDS community organizations) that offer free testing. Such groups often have the 20-minute rapid test, so you know even sooner.
A simple Internet search is usually enough to give you several testing options. It's not even necessary to do it at your doctor's office.