Well, there is strategy called Average down! If you had been using the strategy you may not have lost so much. It is not late now. Double the units you have in all these coin. Any 10 % to 20% increase in price will automatically put you in profit! Keep buying the deep and you won't lose a dime at the end of the day!
Yes exactly, in your remaining funds, you should invest in a more profitable alts, not on the one you loose, in order to gain and get back what you have lost, you have to put more efforts in earning, use some strategies that will help you gain profits as soon as possible, 80% is a huge quantity of bitcoin you must look for alternative income like, investing in some successful ICO or some alts that will help you gain more points.