@K980 it's totally normal to have all kinds of symptoms during b12 start up. I've attached a document that might help although it's a bit confusing. It lists the various symptoms Fredd noticed in himself and others caused by b12 including refeeding induced deficiencies. I have had many of these symptoms.
The main problem is balancing electrolytes. Nausea could be sodium or magnesium deficiency. Also watch out for folate deficiency symptoms. The document discusses that as well.
Update and some good news but a question. Since taking the Riboflavin over the past two weeks my MMA lowered from 607 to 480... however, it is showing Low protein and low globulin. Can that lowering be a by product of cell creation?