How long have you been sick and what testing have you had done? Personally, I first got sick in 2004 and I didn't come to reasonably know what I had until Jan 2008. A doctor first suggested lyme back in 2006 but they ran the other test besides western blot, ELISA, I believe, and it was negative. When I finally got to do the WB in 2008 it was even positive according to CDC standards(or at least, the test results from Igenex had information claiming that to be the case).
Over the last 4 years I've done probably 20+ standard blood tests...and just between 2004 and 2008 I hit up the ER with chest pain(or palpitations if not pain) 4-5 times, done several cardiac ultrasounds, and so on. Back in 2006, I had just went to visit a 3rd general practitioner trying to get answers, and the first thing they suggested was the lyme, did the ELISA, it came back negative, then they sent me to a neurologist, who did a head MRI etc(which only showed some sinus irritation, apparently that's not uncommon), then I got sent to a sleep apnea specialist(because of waking up in the middle of the night with a numb chest). None of that was actually the problem, of course, so I was pretty frustrated to be back at square one. I even went and applied for an extra life insurance knowing they'd run a blood test of their own, I figured I'd try and make Murphy's law work in my favor. That didn't work either, they didn't find anything wrong but as a matter of principle they rated it(charged more money for the insurance)just because of all of the tests in my recent health history! Finally after all that I began combing through known illnesses on the internet again and finally I settled on that it MUST be lyme, ended up doing a WB and CD-57 and therefore, I'm reasonably certain that it is lyme that I have. Though, I'm somewhat intrigued by the WB's results explanation which includes a warning that syphilis and other things can trigger the same antibodies.