I always enjoy when BTC goes down even though my assets are also minus, I also invest in bitcoin for the long term but if I think it's time to sell then I will sell it, not too good if bitcoin hold is very long, we also don't know any good or bad news out there about bitcoin, if it's profit then sell your bitcoin right away, it's better to minus a little than minus up to 50%.
But this will still keep you at loss isn't it? I set up auto trade in order to covert my Bitcoin into USDT whenever price drop from a set margin so that I have USDT which I use to buy more bitcoin than I have as the price drops but USDT remains stable. That's how I make use of the situation by adding more bitcoin and then selling it off during peak. It's not as easy as I have explained it as it breaks our head sometime, but this has worked in my favor many times and I be old suggest all to try this with a lesser amount initially to learn the art.