I don't think I 'believe' I have LADA/Type 1, but what I do believe is that we have not ruled it out.
To start with, there's a decent number of posts even on this site that argue that a negative test for antibodies does not allow one to rule out Type 1/LADA, for example, here:
When my low morning insulin came in, my endo said "that result makes me think a bit. You are not what we think of as a 'typical' Type 2: someone who progresses from insulin resistance to insulin deficiency. You are insulin deficient right of, and have no sign of insulin resistance".
I understand that I am not Type 1 from the view that "Type 1 requires complete or near-complete absence of insulin deficiency".
I understand that I am not LADA from the view that "You should have antibodies and a low C-pep". By the way, though my C-pep came in as 0.9 where the cut-off is 0.8. When it comes to diagnoses, I believe that the cutoffs should be looked at as "fuzzy", because that's how the studies that determine the cut-off work. They say "well, looks like 66% of people with the disease are below this number, so that's the cut-off".
Brian mentioned a few times MODY as a possibility. I will look into that next.