My clinic has advised that I take 1250 mg of magnesium at bedtime. I've been taking this dose twice per day, so now I've moved one of those to bedtime, after the probiotics. I'm hoping that it helps!
Could be from the abx, or could be from the infections (or from herxing).
Inflammation can artificially decrease WBC count because the WBC's are busy and aren't free-floating around in the blood stream (thus can't be detected on the blood test).
Herxing increases inflammation, as does the infection. Plus, Lyme (and some coinfections) can invade and destroy WBC's.
Abx have decreased WBC count as a known side-effect, also.
Best to discuss with your LLMD... There are some supplements that can help.