Sell some of those Altcoins from your account but not all because some are meant and worthy to be hold for a long period of time to go along while waiting for the perfect time until the price bounces back or at least you can assure that you can regain your capital and earn a profit once you sell them. There are also other Altcoins that are unworthy to be hold on anymore due to they are called or coined as 'shitcoins' because ever since the end of the ICO, the project has failed to show progress that is why the project went dead and failed to grow in progress right after the sale. Sort out those types of Altcoins from your account to at least lessen your stress about too many Altcoins you do have. But still it is your decision that matters the most if you will be keep on holding them all or sort out those unworthy one and sell them and just keep on holding into those worthy ones till prices bounces back.