That's why people always say that involving yourself in crypto, one should be knowledgeable of the risks that comes along with it. Cryptocurrency is unstable and it does fluctuate ever so often. One moment ETH is at 3000 dollars, after several days it drops down to 2500 dollars. It is perfectly normal and recoverable, you just have to be patient. One technique is to buy during the dip and hold until the price peaks. Some people panic sell their crypto when they see that the price keeps decreasing, dont do that. Not only will you lose so much of what you invest, you'll also influence the market.