Some people get elevated calcium when using high dose Vit D3.

I would cut back on your Vit D dosing by 50% and see what happens.

The heart will beat faster if the blood pressure falls. So I think you should invest in a blood pressure cuff and start keeping a log of your pressures during the day.

The amount of B12 absorbed orally is quite small. I would think the 100mcg in the B-Right would not be significant. A study measuring absorption has shown only 13mcg in volunteers was absorbed and measured in the blood from a dose of 1000mcg daily.

I would keep a journal of your blood pressures, pulse readings, and food intake, to see if there is a dietary trigger to your symptoms.

When you log your statistics, you can then show them to your doctor, to help him/her evaluate your symptoms.

Once you get your next B12 test, you might have more information at your disposal to decide what to do next. If your test shows over 1000pg/ml, you can cut back on dosing to maybe twice a week.

Too much magnesium can also lower blood pressures. So taking your own measurements would be an excellent way to monitor things. Normally people will excrete excess magnesium via the urine, if the kidneys are working properly. It is very unlikely to have excess magnesium from a supplement, as diarrhea usually happens before any toxicity can mount.

Excess serotonin in the GI tract can cause loose stools, and air hunger. Zoloft may make your GI symptoms worse. If it does, this hint, points to carcinoid syndrome... and should be tested for.
http://en.wikipedia.org/wiki/Carcinoid_syndrome

Also certain blood pressure drugs increase bradykinin too...ACE inhibitors. If you use these, you could have symptoms like you describe.

And also elevated thyroid will cause symptoms like you are having. (this the doctor can screen for with blood tests).

Since your symptoms worsened with the new multivitamin, I'd drop that for now. Study the ingredients carefully...as there may be high B6 in it.