To summarize everything the only way to avoid experiencing panic during the bearish period is to invest an amount that is losable to you.
Have a clear investment plan: Before investing, it is important to have an obvious investment plan that aligns with your financial goals and risk tolerance. Stick to your plan to avoid making sudden changes in response to short-term market changes.
This is where the problem lies because many people actually don’t plan well and that is why you see people losing in bitcoin. Although bitcoin is regarded as one of those stores of values but that doesn’t mean one should invest everything into it. Diversification of funds into other assets (investing in Altcoins are not diversification of portfolio) saves one from panic selling during the bearish period. Also have fiat at hand so that when the bearish period prolongs there’s somewhere to turn to for financial emergencies