Panic

The market will only hand out odds not any certainties. Rather than wondering, can something work, ask what are the odds, and what could i earn if it does agaisnt if it does not, and it is all wrong?”

you can manage any risks much better early on by trying to weigh up the probabillities early on, and not hoping for perfection, if you rely on considering the odds of sucess they are likely to be right more than they are wrong.

panicing when any stock you have starts falling, is if you are honest with yourself is either due to any price changes or a change in the business.

To avoid panic it is better to understand tha business, studying a companies potential risks such as cash flows and profits or losses, can help to avoid any sudden market noise or influnces about the company that may cause you to panic.

By knowing just a bit about a company, any movements are easier to understand in terms of if they are posotive or negative swings drops etc, and an opportunity. 

Your confidence will come from understanding and knowing what stocks you own does not come from just watching movement of prices.