This has been one of the majority problem in the trading space today most average traders who already have average experience on trading mostly have this state of fears in them, In the trading space many average trader have this fear of succeeding, this mostly happens to an average traders or business owners which they likely say, "what if one red trade takes it all alway" they suddenly become more anxious having that fear that they might start all over again.
If you want to do a trade even in an investment is there's always a risk, reason why we have the risk management which you are setting the risk if you made an investment at the first place its the money you are willing to risk or else you will cut the losses and liquidate the number of asset you've been bought. Once you already know how to properly make a risk for the next investment and trading you will do is you can now over come the fear in your investment. Yes only few can be successful but these can be use to learn more so if you see that outcome again you know now what to do.