If you are low in B12 it's very unlikely an over the counter strength supplement would be strong enough to treat it.
Low B12 can often mean very long treatment times as well, i've been taking 2 prescribed tablets per day since November, waiting for Januarys results, if normal (as expected) I will then take 1 tablet per day as a maintenance dose, because the cause of my deficiency is unknown. For those that have injections the time between them decreases, but doesn't stop for a long time.
Would it be an idea to get it checked via your Dr, along with a range of other nutrient tests, who can then prescribe anything necessary?
Also if you were this way before your diagnosis, you could be one of those people (like me) who naturally has a higher hunger level. Sucks. :ymad:
Some ways I tackle it are to ignore it between meals- annoying yes but as I tell myself it's perfectly okay to be hungry, and making sure I drink lots of water both between meals, and when eating so I feel fuller.
Personally I try not to snack between meals (if I feel dizzy etc of course I have something straight away) and having that bit more at mealtimes instead.
I also eat slowly and use a small plate to give the illusion of lots of food.
I am sorry if you've heard and tried those tips before!
Others may find regular small meals and grazing more satisfying.
Perhaps a referral to a dietician who could help you find more ways of being satisfied when it comes to food?