Giddiness and weakness in legs , hands.

I'm having giddiness every now and then for the past six months.  This march i got my vit D and b12 checked and they're 8 and 220 respectively. Very less when compared to normal values. I've been using the supplements for the past 1 month and I find no difference. I still feel giddiness, pain, depression. Unable to concentrate on my work as I'm always tensed on this. I have started taking fish, oranges ,milk and also sun light ... Still giddiness is there sometimes, how long it will take to recover.. I have sinusitis problem also and I have undergone fess surgery also 2 weeks back... Is this giddiness can be improved once my vitamin levels reaches normal level? .. Please help me on this as I am planning get married..