Have you considered taking B12 injections (methylcobalamin, subcutanuous) instead of sublingual tablets? Many of us have absorption problems...
Lipospheric Vit C has helped me a lot.
I myself take:
Lypospheric Vit C - 1 sachet per day, 15 mins before breakfast
Magnesium Citrate - 1000 mg (sometimes 2000) per day
Omega 3 - 3 times 1200 mg per day
Zyflamend - 2 per day
Berberine - 400 mg per day
Resveratrol - 3 times 200 mg per day
B12 - 1 injection per day
with abx, and also started on Houttuynia
Lyme & Bartonella. Sick for about 19 years (34 now). Started treatment August 2012 with abx (ILADS protocol, different combinations) + Buhner's Core Protocol. Leaky gut, heavy metals, EBV, XMRV, erythema nodosum, Hodgkin's Lymphoma at 15, Lyme arthritis, many neurological symptoms, food allergies/intolerances, histamine/chemical intolerance and much more.