The "Psychology of Trading", and the discipline of trading.... are all about "doing what you know* you are supposed to even when you feel like you'd rather not".
* You'll know what you're supposed to do only after you've done enough study. That is, "why" am I supposed to take a certain risk... high probability of success? Favorable risk-reward dynamic? Both? Why should I exercise stop when I'd rather hope the market reverses in my favor so that I can avoid this loss?
Once you understand these... then DOING IT... even when doing so makes you uncomfortable to a degree... is a major component to trading success.
I bought "The Disciplined Trader" years ago. Recommended!!