My SBD does not deposit to Bittrex! I think steem and SBD may be broken right now! I hope they fix is soon. Or are the only exchanges available just scamming!? There hasn't been a good enough discussion for what's going on. I would say hold for now until an announcement from the steem team.
It took around 3 hours for them to process my STEEM Withdraw, while all other currencies were almost instant, if it's not there in a few hours, I think you should make a support request, they seem to reply pretty fast.