I invested $100,000 into ETH when it was at $800. I was wondering if I should sell and re-buy or hold? Will ETH reach $800 again this year? 
No matter what other people will say about this topic the choice is always yours. I know you earned an income out of buying eth at $800 which is a great thing to know. As of now, I really wonder if you still believe in this cryptocurrencies because if yes then you can buy bitcoin again and wait for the right time to sell it once its value increase.