How much is the price of bitcoin when you invest in it? Because if you will sell at loss now, its just shows you only waste your money for investing in crypto since you're not prepared for times like this.

Its quite normal to have worries if the situation is not what we expected it to be. However if you take time learning about how crypto works (the moment you first invest) and aware of the possible scenario that can occur then you're not going to panic. For most of us the best decision now is to hold and take advantage the correction to buy more. Thus think whats more beneficial for you to avoid having regrets.