No it's not halving already. I think the price drop is cause by the DAO disaster and temporary close of a big exchanger's site. The halving will happen on the month of july. Don't worry for the price drop it will rise again, if i were you i will just hold my bitcoins and increase it by buying bitcoin now because the price is low and after halving and the price reach your expectations it's the right time to sell your coins and bring home that good profits .