How do I remember that I still have freedom when I'm under pressure?

You have grasped something powerful: no matter how tight the circumstances, some freedom is always yours, the freedom of how you respond. The trouble is that pressure makes you forget it. In the heat of the moment, it feels like the situation is running you. That forgetting is normal. Everyone does it. The freedom you keep is small but real. You cannot always choose what happens, but you can choose what you do next, the attitude you take, whether you react or pause. Circumstances can take a great deal from you. They cannot take that last inch of choice unless you hand it over. Build a habit for the pressured moments. When you feel gripped, stop and name it: this part is not mine, but this next choice is. One breath, one pause, is often enough to step back into that freedom. You will forget again. That is fine. Each time you remember, the muscle gets a little stronger.