Does any know if poor treatment for thyroid can cause blood sugar to run high? I have both Hypothyroidism and now Type 2 Diabetes. Recently been feeing very tired and achy. Blood sugars in the morning in the low 10s which is quite high for me. I take 175mcg levo and 3x500mg metformin. My B12 was 218 range 150-900 so taking Boost a spray supplement. Any advice as to what to do? GP wont give B12 treatment as says in normal range.