So to deal with kind of acenario is to be prepared by reading reviews, speculation and forecast and out of it will be the basis of your dexisions
it depends on what market you are talking about! in bitcoin there are many whales and market is huge, so you really can't be considered a whale no matter how much bitcoin you have because if the market and other whales are against you, you won't matter.
in altcoins there are two kinds. the manipulated ones and small ones. the manipulated ones like ethereum have a lot of money in a centralized group behind it. they have the foundation and a lot of funds to control the market. nobody can put a dent in it.
in a small coin sometimes it is even possible to become a whale with 1BTC! and yes i have tried and it is possible
Yes, small traders can be manipulated in small markets. However, when it comes to big markets I doubt it can be manipulated by whales.