I have finally got a date for my op to have lump removed from wrist. I have got to have general anaesthetic, and have been told I am morning surgery. I am worried because I have got to have my B12 injection, (which I have done every 3 months) 2 days before the op. I will speak to the hospital before, as I still haven't been told if I have to take my thyroxine as usual on the morning of the op. I take 150mcg, and I have Hashi's.