For me I don't consider it as an opportunity as others have thought because in the first place you already have bought bitcoin at a higher price and it is the reason why you feared a lot about losing your investments. Consider looking at the possibilities on a longer time scale. If you think bitcoin will never reach that value again and you don't want to invest long term then better sell it to cut loses. But if you think that the value could go higher than the buying price in any time later then just hold it np matter what this is up to you.