getting lyme's while on antibiotics

hi all-
i have read on the internet that lyme's tests can forever come back negative if one was taking antibiotics while contracting lyme's disease?
i do not know if i have lyme's disease yet, however, everything else has been ruled out. i got suddenly sick at 23 years old after being perfectly healthy. all my symptoms fit in the lyme picture.
however, at the time that i suspect i could have gotten lyme's i was taking a low dose of doxy as an antimalarial agent. the last time i remember getting bitten by a tick was in africa, where it was embedded in my leg for about four days. it was a couple months after that that i became sick with all kinds of weird symptoms, which have persisted now for 2 years.
i was taking 100mg of doxy. my doc believes this would have been too small a dose to kill the bacteria.
so i am wondering if this would truly affect a lyme's test, even at this point, two years later? it was pretty immediately that i stopped the antibiotics that i became sick.

i am trying to decide if i should try to order the igenex test and have my PCP run it (who doesn't know anything about LD), or if i should go straight to a LLMD (which may be too expensive for me to pay out of pocket without insurance). if lymes is truly a clinical diagnosis, i feel super confidently i would have it. if it needs a positive test, that is where i am confused.

thoughts?

hi,
i have been referred to an ID doc. i suppose it is possible i could have gotten something else. but it seems like, of all the things i could have caught in africa, i don't really fit the picture. i don't have a fever - very low body temp actually. but it's possible.
i don't know if my insurance will cover the igenex lab! but it sounds like i need to get that regardless of if they do or not.

Forgot to ad. My test came back close to positive and I see a llmd. So he clinically made the diagnosis. If you study up on the bands and which ones are lyme specific. Even if your test comes back normal but some of those bands show up a good doc would clinically diagnose lyme.