I've started to get a lot of dandruff lately. whats going on? am i lacking in some sort or vitamin?

Maybe not lacking: Dandruff (seborrhea) is common. Shampoos with zinc, salicylic acid, selenium, or coal tar are sold in many stores. Nizoral shampoo (contains anti-fungal) is also available. Doctors may also recommend cortisone or kenalog (triamcinolone) sprays. Prevent dryness (don't wash hair too often). A primary doctor or dermatologist can look for psoriasis, eczema, or fungal infections if unusual or worrisome scalp symptoms.