That changes every day. It is true that SBD is most of the time of higher value than steem. When it raised up till over 10 USD, Steem was worth some 6 USD. In such a situation, you better change exchange them on the market.
They deleted the "convert" button in the wallet a few days after my bad mistake, so what I did is fortunately not possible anymore.
Sorry to hear you had this problem. It is at least encouraging to know that you had built of that many SBD... it means you can do it again. Just for an experiment, on this post I set the rewards to go 100% SP.