The worst decision about trading I ever did was I bought a coin when the price went down but it turns out the coin prices continue to fall and now I can only hold it and wait for the price back up because I do not want to lose. by selling it cheaply
I think this is not your worst decssion. you bought the coin when that coin price went down that means bit early you bought that coins that's it. don't worry if the price recovers then you will get your investment back with profit. suppose if you bought coin when the price was high then you can consider that as your worst decision.