I also experienced the same thing I made deposit 1.557btc on 19 dec and until now get confirm much from 100 confirmation. but until now too isn't added to my bittrex account.. here my tx hash https://blockchain.info/tx/8368e42ed34311617cd763a7ac20339528e66ae176ee8a122dd7f8a4e27c2001  here my bitcoin wallet on bittrex 1BTCN1npH1fwTXQgGhda6HRxyaqxCaR3Up