Great! You have your investment in the right shape at the right place on the right time. Having BTC on Bittrex is the best thing to do right now. As explained in the post, SBD is sticking to ~ $1 price. A price tag of 0.0004000 BTC on Bittrex or any exchange means roughly $1 as per current BTC rate (which is also falling). The current price is just under $1 (0.00039100).
See if it goes lower than that. The opportunity is massive I think.