Humans evolved with a ‘fight or flight’ psychological mentality when facing danger. FX trading is just not suitable to control emotional fear and prevention of pain at all costs - e.g. fear of missing out, fear of losing which causes pain.

Hence why traders would rather nurse a losing trade, than cut it short, in the hope it would turn in their favour, and so justify that they were right.

So, stress is perfectly natural. Top traders control this stress by accepting it’s part of being successful, especially when high monetary trades are at stake. Like everything else, the more you face this situation the less effect it has.