I do not think you sell your altcoin now because now altcoin price is decreasing and if you sell your altcoin now you will not get any profit, for better you buy bitcoin for future when bitcoin price goes up you can invest in bitcoin with long-term and my advice you better hold the coins you have and wait for the price of bitcoin and altcoin back stable. Base on current prize of bitcoin and other alt-coin market price and is more courage to sell off alt coin and buy bitcoin