What to do depends almost entirely on what coins you are holding, if you are holding good coins like bitcoin or ethereum then probably the best move that you can do is to hold your coins until the next bull market appears, and you can either sell your coins when they reach the price at which you bought or you can decide to keep holding them hoping to get some profits.

However if you took a risk and invested in some coins which are outside of the top 100 then it is very possible that you are never going to recover your money, and as such it may be a good idea to sell now.