I would call the doc's office and tell them your current symptoms so the doc can modify your current treatment if it might help. Don't free lance when things are like this ... It's what the doc is for.
Are you taking a medication to control yeast and a good probiotic? Those two things are pretty much mandatory while taking long term antibiotics.
Ditto what Keith_T says: probiotics are needed to put back the 'good bacteria' that the antibiotics have wiped out along with the 'bad [Lyme] bacteria.
My Lyme doc insisted that we take probiotics while on such a sustained course of antbiotic treatment, because antibiotics kill not only the bad (Lyme) bacteria, but also the good [probiotic] bacteria.
My doc recommended one called 'Saccharomyces boulardii' (a brand name of that is Florastor, and there may be others I'm not aware of). The S.boulardii *really* was helpful to replenish the 'good' bacteria which are accidentally killed by the 'bad' Lyme bacteria.
Check with your doc first, just to be sure s/he has another point of view. Some docs are indifferent to probiotics, but I became a believer.
Let us know how you do, okay? Take care! ... and yes, kicking Lyme is VERY worthwhile!