Re: Is it possible i have a b12 deficiency?
Have you been checked for sleep apnea? Poor sleep quality can give you all of those symptoms.
Unfortunately the more "mild" (as if you could call it that!) symptoms of B12 deficiency are terribly nonspecific, so if your b12 levels are normal and you don't have the more severe, specific symptoms, I would also explore other avenues. Of course, taking extra can't really hurt you, so I'd keep it up.
I would also try 5-htp, fish oil (if you ever go to Costco, the Kirkland Signature enteric-coated variety, in the blue bottle, is pretty high quality) and higher-dose vitamin D supplements (like 2000 iu - 500% of the RDV) for a gentle mood boost and general brain-related benefits.
Unless you are already pretty athletic, I would also try to get a bit more exercise and sunlight - it doesn't take much, an extra 10-20 min per day of either one will give anyone huge rewards in energy and mood benefits. (I get the exact symptoms your describing whenever I don't exercise for a couple days.) Don't overdo it or make any daunting commitments - just take walks or something else mildly active for a few weeks and see how you feel, and get outside and/or sit by a window for a bit whenever the weather is nice.
Lastly, if you have access to a respectable clinic and aren't super freaked-out by it, I would try acupuncture. It works wonders for mood and energy levels for a lot of people I know, and is demonstrably good for you. Although there is debate about whether using Chinese meridians has any benefit compared to random needle placement, acupuncture currently has better outcomes than Western medicine in treating many difficult conditions. Having been basically forced to try it by my mom, I can attest that it is surprisingly effective when I am having muscle spasms or mood problems, even if its not my first choice of therapy because it requires you to sit still in a dim room for half an hour (I always get *so* squirmy).
Let us know how things are going!