If at the moment I advise you not to sell all your altcoin because the market is falling, will probably cause you a loss and in the future will increase again, you will regret it.
Yes that is right just HODL and while doing that you need to learn search as much as you want because for sure it will help you to maximize your profit and minimize your losses. Always remember market is just a cycle up and down and nothing stays forever.
Everyone at times like these when all altcoins and even bitcoins are all red must think back to the very beginning of their decisions as to why they have decided to invest into a specific coin. And this will reveal that they have invested in it because they trusted it and believed in its ideologies and potentials which will really help them to think twice before panic selling(that is if they really did make an effort to do a bit of research about every coin they invested at before throwing funds into them.