+1 for LeBreton's comment. I grind and press my own and have found that apples that are very sweet with strong flowery aromas can make poor cider. They may smell great but after all the sugar has been converted to alcohol there is little depth to the cider. That being said, make another batch to keep you occupied and purchase some acid blend, usually malic, citric and tannic as well as some grape tannins. These ingredients used in small amounts can help to round out an otherwise thin cider. Don't go drinking all of those though. They may shine in another few months!