Hi!
This is going to sound really odd, but I have experienced this too (Blood sugars have run high and when ive managed to correct them, felt low (But havnt been, running aorund the 4.5 - 6 mark), however... This has been my situation.
Bloods run high,
Correct with rapid acting
Feel a bit low
Test @ 4.5 - 6 mmol
Suddenly within minutes relax and feel better,
Ive put this down to being in my mind a tad and as soon as its confirmed that my bloods are OK via test I usually feel better. Almost like the placebo effect .. ish , kind of..