I'd hold my altcoins at least untill autumn. Just relax, forget about them and wait) It's not easy to be patient when everything is falling down. Maybe if you're nervous or have money issues, make a review of your coins and sell the most useless ones. I believe that it's only the beginning and all your coins wil rise.
I do not think that this drop will gonna last just to the autumn Richard Heart predicted for example that it will last 3 years, because previously bitcoin was rising like that for twice , it was a huge grows and then three years dip.
If your portfolio value is dwindles sporadically, there is no reason why you should not panic. In fact, you must start to panic so that you can at least cut your losses and if your plan is to hold, then you have no business in current prices!
Same of my tokens are reduced in value about 10-15 times, but I am still holding, of course It would be a smart thing do to sale them on the peak, but I did not do it, now I do not want to sell them because they are almost worthless, I have only option - to hold and be as it may!:)