I'd like to find out more about lack of B12. I've been unwell for about 7 years after surgery for thyroid hemithyroidectomy. I've seen lots of docs. I've felt like I couldn't breathe properly and waking at night gulping for air and in the morning waking feeling like I'm suffocatinng combined with aching from head to toe, my brain not working properly, numb hip and strange pains here and there, anxiety and feeling very low like everything is colourless. My blood test for B12 came back normal, folate was a bit low but normal for NHS. Vitamin D fine and ferritin ok. I started taking methylcobalmin with a B multivitamin and started feeling a bit better. I added methylfolate 400mcg. I increased the methylcobalain to 1500 mcg daily and feel a lot better. If I stop taking it I feel really ill. ANy ideas what's going on? Could I have a B12 deficiency? I have a really healthy diet with plenty of fresh fruit and veg, tried cutting out caffein but made no difference.