You can call on the phone and ask for the test results. Many doctor's offices will do that.

The B-complex has many things in it...and many people may have issues with an empty stomach.
They typically do not have high dose B12 in them however. If you check your label, you'll see 100mcg or less. The RDA for B12 is2-4mcg/day.

You were really not on your supplement long enough to affect your present neuro symptoms. B12 is stored in the liver, and the movement of it into the spinal fluid and hence into the brain is determined by the blood levels you have. If you are at the old normal 200-250 units in serum, you won't be pushing much into the spinal fluid. Keeping your levels at 1000 will be more effective in getting that B12 into the brain.
1000mcg of B12 is only going to give about 10-13 mcg absorbed.
So the small dose of B12 in a standard B complex is not going to do much. B12 on an empty stomach ALONE does not upset anything.

Another thing that will lower B12 and ruin the methylation process in general is nitrous oxide. This can be found in dental offices when having dental work, may be used as a pre-sedative for minor medical procedures, and also inhaled recreationaly by young people attending RAVEs. Also significant at RAVEs is use of ecstasy and this is very damaging to the brain, and new studies show some permanent damage from this drug alone.

So when you get your methylcobalamin replaced, do 5mg daily on an empty stomach, and by the end of 3 months, you may start seeing some improvements, if that is your main problem.
You should see better and more normal sleeping patterns by then too at least.