a few days ago ethereum experienced a drastic decline. and it turns out it's currently under $ 200! My personal predictions are wrong, and may not be true. what's the next step?

I think vacationing is a good idea while enjoying a vacation !!
At this time, I see that in coinmarketcap and Ethereum, prices fell by more than 9%. but before you have a vacation there is a good idea to buy Ethereum first. Who knows, after you go home, Ethereum prices will rise again, because this coin is very good and no one knows what will happen in the future.