I started taking b6 and b12 and i at same time am ravenously hungry, episodes of lightheaded and a bit irritable, is it the vitamins? is it bad?

I don't think so: I believe there must be another reason for your symptoms. By the way there are many possible causes for these symptoms.

Maybe: B6 is involved in making brain neurotransmitters, serotonin & norepinephrine, so depending on the dose, you may have ramped up production a bit. The maximum daily intake is 100 milligrams/day. Vitamin B12 is important in nerve function as well. The recommended intake is usually cited at 2 to 3 micrograms daily, a little more ok. Try to get these in diet; if supplement, not more than recommended.