Many people infected with Lyme go months (or even years) without being diagnosed. They don't remember a tick bite, they didn't get (or didn't notice) the rash associated with it. Frequently they are misdiagnosed with other "syndromes" (chronic fatigue, fibromyalgia, etc.) and given meds to relieve the symptoms, but the illness is still there. I found the process of getting diagnosed VERY SIMILAR to when we were going through the celiac diagnosis. Even the symptoms (for us) were similar! My son's blood tests were inconclusive (again, a lot like celiac), luckily he DID get the rash and I had saved a picture of it. Otherwise we may never have figured it out.
We got it and we live in the city, don't camp or hike, no woods around, never seen a deer anywhere near our house. No idea where he got bit.
Best of luck to you -