It wouldn't be new for BTC holders for a couple of years to experience bear market(a period of fall in price of Bitcoin , for an unusually short/mid-term period) A period of panic where rational decisions must be taken. If a bear market is inevitable, it has to be handled intricately... No panicking!
First, the bear market isn't there yet. It is speculated that usually September month is bearish for the crypto market, so one should not panic sell if they see some negative movements in the next month. The prices will recover soon and they will go parabolic during the last three months of this bull season.
However, I have experienced the previous bear season and I know that it is not easy to survive that 1 or 2 years of bear market and if you are holding some coins, seeing your portfolio go down every day. You need a big heart not to panic sell and hold your coins throughout that time.